2025 Qualified Affordable Housing Project Investments, Commitment To Be Paid Year Four Qualified Affordable Housing Project Investments, Commitment To Be Paid Year Four Supplemental Disclosure of Cash Flow Information Supplemental Cash Flow Information [Abstract] Gains (Losses) on Available-For-Sale and Transferred Debt Securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member] Actual, amount Banking Regulation, Common Equity Tier One Risk-Based Capital, Actual First Company Statutory Trust 2003 First Company Statutory Trust 2003 [Member] First Company Statutory Trust 2003 State Current State and Local Tax Expense (Benefit) Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Consolidated Entities [Axis] Consolidated Entities [Axis] Preferred shares outstanding (in shares) Preferred Stock, Shares Outstanding Third-party acquisition related costs Business Combination, Acquisition Related Costs Thereafter Lessee, Operating Lease, Liability, Payments, Due after Rolling Year Five TBA hedge Derivative Liability Sale and refinancing of other real estate owned Real Estate Owned, Transfer from Real Estate Owned Cash dividends declared Dividends, Common Stock, Cash Security Exchange Name Security Exchange Name Quarterly Financial Information Disclosure [Abstract] Quarterly Financial Information Disclosure [Abstract] Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Basic and Diluted Earnings Per Share Earnings Per Share Reconciliation [Abstract] Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Operating lease, weighted-average remaining lease term (in years) Operating Lease, Weighted Average Remaining Lease Term Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items] Debt Securities, Held-to-maturity, Credit Quality Indicator [Line Items] Derivatives and Hedging Activities Derivatives, Policy [Policy Text Block] Repurchase agreements and other borrowed funds Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure Shares available to grant to employees and directors (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Schedule of Gain (Loss) on Securities [Table] Schedule of Gain (Loss) on Securities [Table] Intangibles Deferred Tax Liabilities, Intangible Assets Total intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Maturing within one year Finance Lease, Liability, Payments, Due in Next Rolling 12 Months Thereafter Time Deposit Maturities, after Year Five (Gain) loss on dispositions of fixed assets Gain (Loss) on Disposition of Assets Due after ten years Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value Investment securities Interest and Dividend Income, Securities, Operating Maturing one year through two years Finance Lease, Liability, Payments, Due in Rolling Year Two Percentage of bonuses and directors fees for deferral of cash payments Percentage of Bonuses and Directors Fees for Deferral of Cash Payments Percentage of bonuses and directors fees for deferral of cash payments. Maturing four years through five years Finance Lease, Liability, Payments, Due in Rolling Year Five Credit Rating, Moody's [Axis] Credit Rating, Moody's [Axis] Aggregate amortization expense Amortization of core deposit intangibles Amortization of Intangible Assets Core deposit intangible, weighted average useful life (in years) Acquired Finite-lived Intangible Assets, Weighted Average Useful Life TDRs that occurred during the period Troubled Debt Restructuring, Debtor, Current Period [Abstract] Net deferred tax asset (liability) Deferred Tax Assets, Net Restricted stock units and stock options excluded from the diluted average outstanding share calculation (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Operating lease, weighted-average discount rate Operating Lease, Weighted Average Discount Rate, Percent Business Combination and Asset Acquisition [Abstract] Acquisition fair market value adjustments Deferred Tax Assets, Equity Method Investments Business Acquisition [Axis] Business Acquisition [Axis] Condensed Cash Flow Statement [Table] Condensed Cash Flow Statement [Table] Amortized Cost Debt Securities, Amortized Cost Basis This item represents the cost of available-for-sale and held-to-maturity debt securities, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. Net (decrease) increase in accrued interest payable Increase (Decrease) in Interest Payable, Net Income Tax Authority, Name [Axis] Income Tax Authority, Name [Axis] Printing and supplies Supplies Expense Supplemental Cash Flow Information Lessee Lease Cash Flow [Table Text Block] Lessee Lease Cash Flow Equity Award [Domain] Award Type [Domain] Accruing loans 90 days or more past due Financial Asset, Equal to or Greater than 90 Days Past Due [Member] Loans receivable Business Combination, Acquired Receivable, Fair Value Estimated Amortization Expense Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Minimum age required to be considered eligible for plan Minimum Age Required to be Considered Eligible for Plan Minimum age required to be considered eligible for plan. Local Phone Number Local Phone Number Loss (gain) on sale of debt securities Gain (Loss) on Sale of Investments Total before mortgage-backed securities Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value Stock Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Nonrecurring Measurements Fair Value, Nonrecurring [Member] Exercisable (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Condensed Income Statement [Table] Condensed Income Statement [Table] Amortized cost and fair value of debt securities by contractual maturity Investments Classified by Contractual Maturity Date [Table Text Block] Four Years Prior Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year Nonaccrual interest income reversed Financing Receivable Nonaccrual Interest Income Reversed Amount of interest income reversed on financing receivable that went on nonaccrual status during the period. Loan Servicing Transfers and Servicing of Financial Assets [Text Block] Preferred shares, $0.01 par value per share, 1,000,000 shares authorized, none issued or outstanding Preferred Stock, Value, Issued Variable Interest Entity, Not Primary Beneficiary Variable Interest Entity, Not Primary Beneficiary [Member] Number of credit rating categories, highest Number of credit rating categories, highest Number of credit rating categories, highest Retained Earnings Substantially Restricted Retained Earnings [Member] Interest Expense Interest Expense [Abstract] Financing Receivable, Recorded Investment, Past Due [Line Items] Financing Receivable, Past Due [Line Items] Deposits Deposit Liabilities Disclosures [Text Block] (Gain) loss on sale and write-downs of other real estate owned, net Gains (Losses) on Sales of Other Real Estate Discount (premium) on PCD loans Financing Receivable, Purchased with Credit Deterioration, Discount (Premium) Fair Value Fair Value Debt Securities, Held-to-maturity, Fair Value Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Credit Rating, Standard & Poor's [Axis] Credit Rating, Standard & Poor's [Axis] Property, Plant and Equipment Property, Plant and Equipment [Line Items] Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Finance lease, financing cash flows Finance Lease, Principal Payments Tax benefit of operating loss carryforwards Other Tax Expense (Benefit) Maturities of Time Deposits Maturities of Time Deposits [Abstract] Operating Leases Lessee, Operating Lease, Liability, Payment, Due, Rolling Maturity [Abstract] Provision for credit loss loans Provision for Loan and Lease Losses Basic earnings per share (in dollars per share) Earnings Per Share, Basic Loans Receivable, Net Financing Receivables [Text Block] Due after five years through ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Amortized Cost Accruing loans 30-59 days past due Financial Asset, 30 to 59 Days Past Due [Member] Condensed Statements of Financial Condition Condensed Balance Sheet [Table Text Block] Loans receivable, net Loans receivable Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss Sublease income Sublease Income Dividends from subsidiaries Investment Income, Dividend Beginning balance (in shares) Ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Combined Approach Combined Approach Valuation Technique [Member] Combined Approach [Member] Other expenses Total other expenses Other operating expenses Other Noninterest Expense Reclassifications adjustments for amortization included in net income for transferred securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-For-Sale, Amortization Included In Net Income, Parent [Member] AOCI, Accumulated Gain (Loss), Debt Securities, Available-For-Sale, Amortization Included In Net Income, Parent Deferred Compensation Plan Deferred Compensation Plan [Member] deferred compensation plan. Fair Value Measurement [Domain] Fair Value Measurement [Domain] Well capitalized requirement, ratio Banking Regulation, Total Risk-Based Capital Ratio, Well Capitalized, Minimum Summary of TDRs Financing Receivable, Troubled Debt Restructuring [Table Text Block] Cumulative Effect, Period of Adoption, Adjustment Cumulative Effect, Period of Adoption, Adjustment [Member] Pass Pass [Member] Net deferred tax asset (liability) Deferred Tax Liabilities, Net Gross amounts of recognized assets Derivative Asset, Fair Value, Gross Asset Depreciation of premises and equipment Deferred Tax Liabilities, Property, Plant and Equipment Interest receivable, held-to-maturity debt securities Interest receivable, held-to-maturity debt securities Carrying amount as of the balance sheet date of interest earned but not received on held-to-maturity debt securities. Unrealized gains (losses) on derivatives used for cash flow hedges Amount of gain (loss) recognized in OCI Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax 2024 Time Deposit Maturities, Year Three Liabilities assumed Noncash or Part Noncash Acquisition, Value of Liabilities Assumed Other Consumer Consumer Portfolio Segment [Member] Entity Voluntary Filers Entity Voluntary Filers Fair Value, Option, Quantitative Disclosures [Line Items] Fair Value, Option, Quantitative Disclosures [Line Items] Proceeds from sales and calls of debt securities and associated gains and losses Gain (Loss) on Securities [Table Text Block] Financial Assets Assets, Fair Value Disclosure [Abstract] Derivative, cap interest rate Derivative, Cap Interest Rate Level 1 Fair Value, Inputs, Level 1 [Member] Investing Activities Net Cash Provided by (Used in) Investing Activities [Abstract] Other liabilities Other Liabilities Loan portfolio aging analysis Financing Receivable, Past Due [Table Text Block] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Entity Small Business Entity Small Business Present value of lease payments Lessee, Operating Lease, Liability, Payment, Due [Abstract] Financing receivable, allowance for credit loss Financing Receivable, Allowance for Credit Loss [Table Text Block] Fair value measurement transfers from one level to another Fair Value Measurement Transfers From One Level To Another Fair Value Measurement Transfers From One Level To Another Finite-Lived Intangible Assets Finite-Lived Intangible Assets [Line Items] Deferred compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation Total Time Deposits Tax benefit of units that vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Tax Benefit Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Tax Benefit Operating lease liabilities Deferred Tax Assets Operating Lease Liabilities Amount of deferred tax asset attributable to deductible temporary differences from operating lease liabilities. Liabilities and Stockholders’ Equity Liabilities and Equity [Abstract] TBA hedge Interest Rate Swap [Member] FNB (UT) Statutory Trust II FNBUTStatutoryTrustII [Member] FNB (UT) Statutory Trust II Entity Interactive Data Current Entity Interactive Data Current Period past due to consider loans as non accrual Period Past Due to Consider Loans as Non Accrual Period Past Due to Consider Loans as Non Accrual 2025 Finite-Lived Intangible Asset, Expected Amortization, Year Four Core Deposits Intangibles Core Deposits [Member] Accrued expenses and other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Liabilities Gross realized gains Debt Securities, Available-for-sale, Realized Gain Retirement Plan Name [Axis] Retirement Plan Name [Axis] Debt securities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Marketable Securities Amount of investments in debt and equity securities, including, but not limited to, held-to-maturity, trading and available-for-sale acquired at the acquisition date. Standard & Poor's, AAA Rating Standard & Poor's, AAA Rating [Member] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Deposits Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits Amount of deposits assumed at the acquisition date Unrecognized tax benefits Unrecognized Tax Benefits Time deposits that meet or exceed FDIC Insurance limit Time Deposits That Meet Or Exceed FDIC Insurance Limit The aggregate amount of domestic time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations that meet or exceed the FDIC Insurance limit. Total gross deferred tax assets Deferred Tax Assets, Gross Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Other Expenses Other Operating Income and Expense [Text Block] Entity Address, State or Province Entity Address, State or Province Other borrowed funds Other Borrowings Deferred tax asset Deferred Income Tax Assets, Net Stock issued in connection with acquisitions Stock Issued During Period, Value, Acquisitions Loan expenses Loan-Related Expenses Loan-related expenses. Due after five years through ten years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling after Five through Ten Years Exercisable (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Current Year Acquisitions Current Year Acquisitions [Member] Consists of all acquisitions occurring during the current year. Premises and Equipment, Net of Accumulated Depreciation Property, Plant and Equipment, Net, by Type [Abstract] Maximum period of original maturity to be included in cash and cash equivalents Maximum Period Of Original Maturity To Be Included In Cash And Cash Equivalents Maximum Period Of Original Maturity To Be Included In Cash And Cash Equivalents Income tax penalties and interest accrued Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Accounting Policies [Abstract] Average remaining contractual term on outstanding stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Derivative Instrument [Axis] Derivative Instrument [Axis] Loan Servicing Rights Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block] Federal Current Federal Tax Expense (Benefit) Operating lease, lease liabilities Total present value of lease payments Operating Lease, Liability Document Transition Report Document Transition Report Finance lease, weighted-average discount rate Finance Lease, Weighted Average Discount Rate, Percent Unrecognized compensation expense, recognized over weighted-average period Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Beginning balance (in dollars per share) Ending balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Net (decrease) increase in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Glacier Capital Trust II Glacier Capital Trust II [Member] Glacier Capital Trust II Carrying amounts and estimated fair values of financial instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Period past due to consider loan as purchased credit-deteriorated loan Period Past Due to Consider Loan As Purchased Credit-Deteriorated Loan Period Past Due to Consider Loan As Purchased Credit-Deteriorated Loan Amortization of ROU assets Finance Lease, Right-of-Use Asset, Amortization Commercial mortgage-backed securities Commercial Mortgage Backed Securities [Member] Other real estate owned and foreclosed assets Other Real Estate, Foreclosed Assets, and Repossessed Assets Mortgage-backed securities Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Other Commitments [Table] Other Commitments [Table] Tax effect Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax Audit Information [Abstract] Audit Information [Abstract] Debt Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Legal Entity [Axis] Legal Entity [Axis] Add: dilutive restricted stock units and stock options (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Debt Securities Marketable Securities, Policy [Policy Text Block] Net income Business Acquisition, Pro Forma Net Income (Loss) Collateral-dependent impaired loans, net of ACL Collateral Dependent Impaired Loans Owned Fair Value Disclosure Collateral dependent impaired loans owned fair value disclosure. Allowance for credit losses Deferred Tax Asset, Tax Deferred Expense, Reserve and Accrual, Financing Receivable, Allowance for Credit Loss Net Interest Income Interest Income (Expense), Net Allowance for loan and lease losses Financing Receivable, Allowance for Credit Loss [Roll Forward] Pre-modification recorded balance Financing Receivable, Troubled Debt Restructuring, Premodification Notes receivable, related parties Notes Receivable, Related Parties Schedule of Other Expenses Schedule of Other Operating Cost and Expense, by Component [Table Text Block] Post-modification recorded balance Financing Receivable, Troubled Debt Restructuring, Postmodification Other Comprehensive Income (Loss), Net of Tax Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Entity [Domain] Entity [Domain] Dividends declared per share (in dollars per share) Cash dividends declared per share (in dollars per share) Common Stock, Dividends, Per Share, Declared Due after one year through five years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost Credit earning rate as a percentage of return on equity Credit Earning Rate as Percentage of Return on Equity Credit earning rate as a percentage of return on equity. Identifiable assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] Stock Options Share-based Payment Arrangement, Option [Member] Unused lines of credit Commitment to Extend Credit [Member] Commitment to Extend Credit [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Equity [Abstract] Equity [Abstract] Comprehensive Income Comprehensive Income, Policy [Policy Text Block] Tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Percent Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Financing Receivable, Troubled Debt Restructuring [Table] Measurement Input Type [Domain] Measurement Input Type [Domain] Dividends declared during the period but not paid Dividends Declared But Not Paid During The Period Dividends Declared But Not Paid During The Period Origination of notes receivable from related parties Origination of Notes Receivable from Related Parties Less than 12 months, fair value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months Finance lease, weighted-average remaining lease term Finance Lease, Weighted Average Remaining Lease Term Minimum capital requirement, ratio Banking Regulation, Tier One Leverage Capital Ratio, Capital Adequacy, Minimum Percentage of salary for deferral of cash payments Percentage of Salary for Deferral of Cash Payments Percentage of salary for deferral of cash payments. Loans Receivable Financing Receivable [Policy Text Block] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Maturing three years through four years Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Four Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Document Fiscal Year Focus Document Fiscal Year Focus Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Investments in variable interest entities Payments to Acquire Other Investments Paid-in Capital Additional Paid-in Capital [Member] Acquisitions Servicing Asset At Amortized Cost, Acquisitions Servicing Asset At Amortized Cost, Acquisitions Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Net interest income and non-interest income Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Maximum period up to which purchase price of business is allocated to assets acquired and liabilities assumed Maximum Period up to Which Purchase Price of Business is Allocated to Assets Acquired and Liabilities Assumed Maximum Period up to Which Purchase Price of Business is Allocated to Assets Acquired and Liabilities Assumed. Accrued interest payable Interest Payable Maturing within one year Lessee, Operating Lease, Liability, Payments, Due Next Rolling Twelve Months Collateral Held [Domain] Collateral Held [Domain] Regulatory Capital Regulatory Capital Requirements under Banking Regulations [Text Block] Tier 1 capital (to risk-weighted assets) Banking Regulation, Tier One Risk-Based Capital [Abstract] Servicing Asset at Amortized Cost Servicing Asset at Amortized Cost [Table Text Block] Stock-based compensation and related taxes APIC, Share-based Payment Arrangement, Restricted Stock Unit, Increase for Cost Recognition Net increase in other liabilities Increase (Decrease) in Other Operating Liabilities Carrying Value of Repurchase Agreements by Maturity and Category of Collateral Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table Text Block] Maximum Range Maximum [Member] Effective income tax rate reconciliation Effective Income Tax Rate Reconciliation, Percent [Abstract] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Share-based Payment Arrangement [Abstract] Lease Summary Lessee Lease Description [Table Text Block] Disclosure of information about lessee's leases. Fair value of servicing rights Servicing Asset at Fair Value, Amount Size of company eligible for Tier 1 grandfather provision Size of company eligible for Tier 1 grandfather provision Size of company eligible for Tier 1 grandfather provision. Award Type [Axis] Award Type [Axis] TDRs that subsequently defaulted Troubled Debt Restructuring Note, Debtor [Abstract] Glacier Capital Trust III Glacier Capital Trust III [Member] Glacier Capital Trust III Financing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Total stockholders’ equity Balance Balance Stockholders' Equity Attributable to Parent Business Combination And Intangible Assets Business Combination And Intangible Assets, Policy [Policy Text Block] Business Combination And Intangible Assets, Policy City Area Code City Area Code Schedule of Financing Receivable, Allowance for Credit Losses [Table] Financing Receivable, Allowance for Credit Loss [Table] Total capital (to risk-weighted assets) Banking Regulation, Total Capital [Abstract] Summary of Subordinated Debentures Terms of Subordinated Debentures [Table Text Block] Terms of subordinated debentures. Checking and operating expenses Deposit-Related Expenses Deposit related expenses other than interest expense. Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Gross Unrealized Gains Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain Useful life of premises and equipment Property, Plant and Equipment, Useful Life Securities Sold Under Agreements to Repurchase Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items] Stockholders’ Equity Stockholders' Equity Attributable to Parent [Abstract] Income Tax Authority, Name [Domain] Income Tax Authority, Name [Domain] Due after one year through five years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value ROU assets Right-of-Use Asset Amount of lessee's right to use underlying asset under finance and operating leases. Miscellaneous loan fees and charges Miscellaneous Loan Fees And Charges Miscellaneous loan fees and charges on residential real estate, commercial, agriculture, and consumer loans. Residential real estate loans Interest and Fee Income, Loans, Consumer, Real Estate Long-term Operating Lease, Liability, Noncurrent Total lease payments Finance Lease, Liability, Payment, Due Total current income tax expense Current Income Tax Expense (Benefit) Federal reserve balance or cash on hand required Federal Reserve Balance or Cash on Hand Required Federal Reserve balance or cash on hand required. Income tax benefit related to compensation expense Share-based Payment Arrangement, Expense, Tax Benefit Minimum number of days delinquent to charge off loans Financing Receivable, Threshold Period Past Due, Writeoff1 Threshold period for when financing receivable is considered past due to write off as uncollectible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Equity in undistributed net income of subsidiaries Subsidiary income in excess of dividends distributed Subsidiary Income (in Excess of ) Less than Dividends Distributed Subsidiary Income (in Excess of ) Less than Dividends Distributed Income before equity in undistributed net income of subsidiaries Income Before Equity in Undistributed Earnings of subsidiaries Income before equity in undistributed earnings of subsidiaries. Age 50 and Over Employee Age 50 and Over [Member] Employee age of 50 and over for determination of maximum annual contributions per employee. Consideration transferred, identifiable net assets acquired and resulting goodwill Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Finance lease, lease liabilities Total present value of lease payments Finance Lease, Liability Intercompany charges for services Intercompany Charges for Services Intercompany charges for services. Business Acquisition Business Acquisition [Line Items] Total gross deferred tax liabilities Deferred Tax Liabilities, Gross Percentage of amount out of first specific percent of employee's contribution matched under plan Defined Contribution Plan, Employer Matching Contribution, Percent of Match Due after ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost Income Statement [Abstract] Income Statement [Abstract] Selling costs Measurement Input, Cost to Sell [Member] Entity Registrant Name Entity Registrant Name Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, by Asset Class [Domain] Asset Class [Domain] Operating lease ROU assets Deferred Tax Liabilities Operating Lease ROU Assets Amount of deferred tax liability attributable to taxable temporary differences from operating lease ROU assets. Summary of net deferred tax asset Components of Deferred Tax Assets and Liabilities [Abstract] Total debt securities Debt Securities Operating Loss and Tax Credit Carryforwards [Table] Operating Loss and Tax Credit Carryforwards [Table] Operating Loss and Tax Credit Carryforwards [Table] Repurchase agreements Securities Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement Other real estate Real Estate [Member] Accrued income and other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Assets Amount of other assets acquired at the acquisition date. Forfeited (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Federal and state income tax expense Total income tax expense Income tax benefit Federal and state income tax expense Income Tax Expense (Benefit) Other Commitments [Domain] Other Commitments [Domain] Reclassification adjustments for gains and transfers included in net income AOCI, Accumulated Gain (Loss), Debt Securities, Available-For-Sale, Gains And Transfers Included In Net Income, Parent [Member] AOCI, Accumulated Gain (Loss), Debt Securities, Available-For-Sale, Gains And Transfers Included In Net Income, Parent Consumer and other loans Interest and Fee Income, Loans, Other Consumer Accumulated Other Comprehensive Loss [Table] Accumulated Other Comprehensive Income (Loss) [Table] Entity Tax Identification Number Entity Tax Identification Number Impairment losses on receivables related to contracts with customers Capitalized Contract Cost, Accumulated Impairment Document Fiscal Period Focus Document Fiscal Period Focus Total lease payments Lessee, Operating Lease, Liability, to be Paid Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Tax credits and other tax benefits recognized Affordable Housing Tax Credits and Other Tax Benefits, Amount Net decrease (increase) in accrued interest receivable Increase (Decrease) in Accrued Interest Receivable, Net Stock-based Compensation Share-based Payment Arrangement [Policy Text Block] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Statement of Financial Position [Abstract] Condensed Statements of Financial Condition Statement of Financial Position [Abstract] Number of years for home equity loan origination term Number Of Years For Home Equity Loan Origination Term Number Of Years For Home Equity Loan Origination Term Aggregate intrinsic value of non-vested units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested Summary of repayment through operation or sale of collateral Financing Receivable Repayment Through Operation Or Sale Of Collateral [Table Text Block] Tabular Disclosure of Financing Receivable Repayment Through Operation Or Sale Of Collateral. Unrecognized compensation expense Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Glacier Bank Glacier Bank [Member] Glacier Bank Property, Plant and Equipment, Type [Domain] Long-Lived Tangible Asset [Domain] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Other real estate owned Other Real Estate Owned Fair Value Disclosure Other real estate owned fair value disclosure. Pre-Tax Gains or Losses Derivative Instruments, Gain (Loss) [Line Items] Unrecognized compensation expense Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Thereafter Finance Lease, Liability, Payments, Due in Rolling after Year Five Certified Development Entities Certified Development Entities [Member] Certified development entities. Sales Comparison Approach Valuation, Market Approach [Member] Substandard Substandard [Member] Equity Component [Domain] Equity Component [Domain] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Tax credit compliance period Tax Credit Compliance Period The period in which a tax credit project must stay in compliance for the investor to keep the tax credits. Non-marketable equity securities Nonmarketable Securities Equity Securities Non marketable securities, equity securities. Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Consolidated VIEs Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Fair value of Company shares issued Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Deferred tax assets Components of Deferred Tax Assets [Abstract] External Credit Rating, Moody's [Domain] External Credit Rating, Moody's [Domain] Total financial assets Financial Assets Fair Value Disclosure Financial assets fair value disclosure. Period of employment required to be eligible for plan Period Of Employment Required To Be Eligible For Plan Period Of Employment Required To Be Eligible For Plan Stock issued in connection with acquisitions (in shares) Stock Issued During Period, Shares, Acquisitions Other income Other Income Debt Securities, Held-to-maturity, Credit Quality Indicator [Table] Debt Securities, Held-to-maturity, Credit Quality Indicator [Table] Outstanding commitments Other Commitment Available-for-Sale Available-for-sale Securities, Debt Maturities [Abstract] Liabilities Liabilities Liabilities [Abstract] Stock issuances under stock incentive plans Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Reclassification adjustment for securities transferred from available-for-sale to held-to-maturity OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), before Tax Weighted Average Range Weighted Average [Member] Available-for-sale debt securities Deferred Tax Asset, Debt Securities, Available-for-Sale, Unrealized Loss Short-term Finance Lease, Liability, Current Income Before Income Taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Level 2 Fair Value, Inputs, Level 2 [Member] Auditor Location Auditor Location Deferred Compensation Plan Acquired Deferred Compensation Plan Acquired [Member] Deferred Compensation Plan Acquired [Member] Total, fair value Debt Securities, Available-for-sale, Unrealized Loss Position Adjustment to comparables Measurement Input, Comparability Adjustment [Member] Financing Receivable, Credit Quality Indicator [Line Items] Financing Receivable, Credit Quality Indicator [Line Items] Commercial Real Estate Commercial Real Estate Portfolio Segment [Member] Amortized Cost Debt Securities, Available-for-sale, Amortized Cost 2026 Qualified Affordable Housing Project Investments, Commitment To Be Paid Year Five Qualified Affordable Housing Project Investments, Commitment To Be Paid Year Five Transfer of debt securities from held-to-maturity to available-for-sale Transfer from Investments Interest on lease liabilities Finance Lease, Interest Expense Other real estate owned and foreclosed assets Foreclosed Real Estate Expense Minimum number of quarters required to be eligible for employer discretionary contribution Minimum number of quarters required to be eligible for employer discretionary contribution Minimum number of quarters required to be eligible for employer discretionary contribution of the profit sharing plan. Basic and diluted earnings per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Minimum capital requirement, amount Banking Regulation, Total Risk-Based Capital, Capital Adequacy, Minimum Financial Liabilities Financial Liabilities Fair Value Disclosure [Abstract] Minimum capital requirement, ratio Banking Regulation, Tier One Risk-Based Capital Ratio, Capital Adequacy, Minimum Fair value measurement of assets measured at fair value on a non-recurring basis Fair Value Measurements, Nonrecurring [Table Text Block] Present value of lease payments Finance Lease, Liability, Payment, Due [Abstract] Income tax return jurisdictions and years subject to examination Summary of Income Tax Examinations [Table Text Block] Title of 12(b) Security Title of 12(b) Security Mortgage-backed securities Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost Common shares authorized (in shares) Common Stock, Shares Authorized Other real estate owned, measurement input Other Real Estate Owned, Measurement Input Net income available to common stockholders, diluted Net Income (Loss) Available to Common Stockholders, Diluted Gross Unrealized Losses Securities, Gross Unrealized Loss Accumulated In Investments Amount of accumulated unrealized loss before deducting unrealized gain on investments in available-for-sale and held-to-maturity securities impacting investments. Net income available to common stockholders, basic Net Income (Loss) Available to Common Stockholders, Basic Total before mortgage-backed securities Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Document Type Document Type Fair value of consideration transferred Business Combination, Consideration Transferred [Abstract] 2026 Time Deposit Maturities, Year Five Common Equity Tier 1 (to risk-weighted assets) Banking Regulation, Common Equity Tier One Risk-Based Capital [Abstract] Reclassification adjustment for losses included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Non-Accrual and 90 Days or More Past Due Nonperforming Financial Instruments Non-Accrual and 90 Days or More Past Due [Member] Category status of financial instruments in which payments are 90 days or more past due or on non-accrual in accordance with the terms of the contract. Financial instruments include, but are not limited to, financing receivables, loans, debt, and investments. Stock-based Compensation Plans Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Fair Value by Measurement Frequency [Axis] Measurement Frequency [Axis] Total non-interest income Non-interest income Noninterest Income Forecasted notional amount Derivative Liability, Notional Amount Components of Lease Expense Lease, Cost [Table Text Block] Severity rate on available-for-sale debt securities in an unrealized loss position Available-for-sale, Securities in Unrealized Loss Positions, Severity Rate Available-for-sale, Securities in Unrealized Loss Positions, Severity Rate Corporate bonds Corporate Bond Securities [Member] Interest bearing cash deposits Interest-bearing Deposits in Banks and Other Financial Institutions Total financial liabilities Financial Liabilities Fair Value Disclosure Mergers and Acquisitions Mergers, Acquisitions and Dispositions Disclosures [Text Block] Total identifiable assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets 2023 Qualified Affordable Housing Project Investments, Commitment To Be Paid Year Two Qualified Affordable Housing Project Investments, Commitment To Be Paid Year Two Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Bank-owned life insurance income, net Life Insurance, Corporate or Bank Owned, Change in Value Mortgage Banking [Abstract] Average remaining contractual term on non-vested units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms Net amortization of purchase accounting adjustments and deferred loan fees and costs Accretion (Amortization) Of Discounts And Premiums, Business Combinations The sum of the periodic adjustments of the differences between business combination asset and liability fair values and carrying values that are charged against earnings. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method. Other Other Cost and Expense, Operating Activity for restricted stock units Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Thereafter Qualified Affordable Housing Project Investments, Commitment To Be Paid Thereafter Qualified Affordable Housing Project Investments, Commitment To Be Paid Thereafter Fair Value of Assets and Liabilities Fair Value Disclosures [Text Block] Recorded balance Financing Receivable, Troubled Debt Restructuring, Subsequent Default Assets with a recorded change from re-measuring at fair value on a non-recurring basis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract] Cash on hand and in banks Cash and Due from Banks Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Axis] Amortization Servicing Asset at Amortized Cost, Amortization Minimum capital requirement, amount Banking Regulation, Tier One Leverage Capital, Capital Adequacy, Minimum 2024 Finite-Lived Intangible Asset, Expected Amortization, Year Three Special Mention Special Mention [Member] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Deferred tax liabilities Deferred Tax Liabilities, Gross [Abstract] Dividends payable Dividends Payable Net increase in securities sold under agreements to repurchase Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase Derivative [Table] Derivative [Table] Income Revenues [Abstract] Interest Income Interest and Dividend Income, Operating [Abstract] Transferred debt securities Deferred Tax Liabilities, Transfers From Available-For-Sale To Held-To-Maturity Debt Securities Deferred Tax Liabilities, Transfers From Available-For-Sale To Held-To-Maturity Debt Securities Document Period End Date Document Period End Date Equity received from (contributed to) subsidiaries Payments to Acquire Additional Interest in Subsidiaries Due after one year through five years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling after One through Five Years Summarized unaudited quarterly financial data Quarterly Financial Information [Table Text Block] Stock Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Consolidated Entities [Domain] Consolidated Entities [Domain] State taxes, net of federal income tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent State Deferred State and Local Income Tax Expense (Benefit) Premises and equipment, net of accumulated depreciation Property, Plant and Equipment [Table Text Block] 2025 Time Deposit Maturities, Year Four Income Statement Location [Domain] Income Statement Location [Domain] Net premises and equipment, excluding ROU assets Property, Plant and Equipment, Net Accrued interest receivable Interest Receivable Maturing two years through three years Finance Lease, Liability, Payments, Due in Rolling Year Three Gain or loss on sale of investments Gain (Loss) on Investments [Abstract] Earnings Per Share [Abstract] Earnings Per Share [Abstract] Percentage of likelihood for term more likely than not as it relates to income taxes Percentage of Likelihood for Term More Likely Than Not Percentage of likelihood for term more likely than not. Cash and cash equivalents Cash, Cash Equivalents, and Federal Funds Sold Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Repurchase Agreements and Similar Transactions, Maturity Periods [Axis] Premises and equipment, gross Property, Plant and Equipment, Gross Total income Revenues Reclassification adjustments for gains included in net income (loss) Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Debit card expenses Debit Card Expense Debit card expense. Debt securities, held-to-maturity Held-To-Maturity Investments, Fair Value Disclosure Fair value portion of held-to-maturity investment securities. Condensed Statements of Operations and Comprehensive Income Condensed Income Statement [Table Text Block] Impairment losses Affordable Housing Project Investment, Write-down, Amount Outstanding Commitments Other Commitments [Line Items] Beginning balance (in dollars per share) Ending balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Interest bearing deposits Interest-bearing Deposit Liabilities Expenses Costs and Expenses [Abstract] Number of securities Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions Gross realized losses Held-To-Maturity Securities, Sold Security, Realized Loss This item represents the loss realized on the sale of held-to-maturity securities disposed of during the period. Additionally, this item may include, if not separately presented, any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt securities which are being or have been recognized in earnings during the period. Origination of loans held for sale Payments for Origination and Purchases of Loans Held-for-sale Variable Interest Entities Schedule of Equity Method Investments [Line Items] Finance lease, accumulated depreciation Finance Lease, Right-of-Use Asset, Accumulated Amortization Financing receivable, allowance for credit losses, number of components Financing Receivable, Allowance for Credit Losses, Number of Components Financing Receivable, Allowance for Credit Losses, Number of Components Entity Current Reporting Status Entity Current Reporting Status Weighted- Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Other income Noninterest Income, Other Operating Income Net amortization of debt securities Accretion (Amortization) of Discounts and Premiums, Investments Amortization of debt modification costs Amortization of Debt Issuance Costs Deposits Deposits (Textual) [Abstract] Deposits textual. Maturities, prepayments and calls of held-to-maturity debt securities Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities Discount rate Measurement Input, Discount Rate [Member] Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Gain (Loss) on Sale of Loans Gain (Loss) on Sale of Loans [Member] Primary financial statement caption encompassing gain (loss) on sale of loans. 2022 Time Deposit Maturities, Year One Net increase in deposits Increase (Decrease) in Deposits Cash Flow Hedge: Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract] Well capitalized requirement, amount Banking Regulation, Total Risk-Based Capital, Well Capitalized, Minimum Income Taxes Income Tax, Policy [Policy Text Block] Troubled Debt Restructurings Financing Receivable, Troubled Debt Restructuring [Line Items] Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Income (Loss) [Line Items] Total non-interest expense Non-interest expense Noninterest Expense Entity Address, Postal Zip Code Entity Address, Postal Zip Code Other borrowed funds Interest Expense, Other Financing receivable, allowance for credit losses, forecasting period Financing Receivable, Allowance for Credit Losses, Forecasting Period Financing Receivable, Allowance for Credit Losses, Forecasting Period Due after five years through ten years Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value Average outstanding shares - diluted (in shares) Average outstanding shares - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Securities sold under agreements to repurchase Securities Sold under Agreements to Repurchase Federal and State Income Taxes Income Tax Disclosure [Text Block] Number of bank divisions Number of Bank Divisions Number of Bank Divisions Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Fair value of assets acquired Noncash or Part Noncash Acquisition, Value of Assets Acquired Activity for stock options Share-based Payment Arrangement, Option, Activity [Table Text Block] Rate Structure Debt Instrument, Basis Spread on Variable Rate Due within one year Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost Subordinated debentures Interest Expense, Junior Subordinated Debentures Statement of Cash Flows [Abstract] Condensed Statements of Cash Flows Statement of Cash Flows [Abstract] Loans receivable, net of ACL Loans Receivable, Fair Value Disclosure Occupancy and equipment Occupancy, Net Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Entity Address, Address Line One Entity Address, Address Line One Net increase in other borrowed funds Net decrease in other borrowed funds Proceeds from (Repayments of) Other Debt Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Loan originations Payments for Loans Originated or Acquired Payments for loans originated or acquired. Allowance for Credit Losses - Loans Receivable Financing Receivable, Allowance for Credit Losses, Policy for Uncollectible Amounts [Policy Text Block] Operating Activities Net Cash Provided by (Used in) Operating Activities [Abstract] Principles of Consolidation Consolidation, Policy [Policy Text Block] Entity Shell Company Entity Shell Company Tax withholding payments for stock-based compensation Tax withholding payments for stock-based compensation Payment, Tax Withholding, Share-based Payment Arrangement Capital adequacy guidelines and compliance Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Revenue from contracts with customers Revenue from Contract with Customer, Including Assessed Tax Percent rate for non-elective safe harbor contribution as component of profit sharing plan Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Current Fiscal Year End Date Current Fiscal Year End Date Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Interest rate expense recorded on interest rate swap Derivative, Cost of Hedge Proceeds from long-term Federal Home Loan Bank advances Proceeds from FHLBank Borrowings, Financing Activities Two Years Prior Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year Statement [Table] Statement [Table] Impaired loans, measurement input Impaired Loans, Measurement Input Value of input used to measure impaired loans. Collateral dependent loans Collateral Dependent Loans Amortized Cost Basis of Financing Receivable, Repayment through Operation or Sale of Collateral Accounting Guidance Adopted in 2021 and Pending Adoption at December 31, 2021 New Accounting Pronouncements, Policy [Policy Text Block] Other Deferred Tax Assets, Other Other Commitments [Axis] Other Commitments [Axis] Held-to-maturity Debt Securities, Held-to-maturity, Sale or Transfer of Investment [Abstract] Range [Axis] Statistical Measurement [Axis] Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration] Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration] Long-term Finance Lease, Liability, Noncurrent Goodwill Net carrying value at beginning of period Net carrying value at end of period Goodwill Core deposit intangible, net Net carrying value Finite-Lived Intangible Assets, Net Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Less than 12 months, unrealized loss Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Number of reporting units subsequent to aggregation for goodwill assessment Number of Reporting Units Subsequent to Aggregation for Goodwill Assessment Number of Reporting Units Subsequent to Aggregation for Goodwill Assessment Operating Lease, Liability, Statement of Financial Position [Extensible List] Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration] Forward commitments to sell TBA securities Forward Contracts [Member] Schedule of Goodwill Schedule of Goodwill [Table Text Block] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Loans receivable Loans receivable Total Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss 2024 Qualified Affordable Housing Project Investments, Commitment To Be Paid Year Three Qualified Affordable Housing Project Investments, Commitment To Be Paid Year Three Age Under 50 Employee Age Under 50 [Member] Employee age of under 50 for determination of maximum annual contributions per employee. Operating lease cost Operating Lease, Cost Loans pledged as collateral Loans Pledged as Collateral Gain on sale of loans Gain on sale of loans Gain (Loss) on Sales of Loans, Net 12 months or longer, unrealized loss Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Maximum percentage of annual compensation allowable for contribution by eligible employees Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Deferred tax benefit Total deferred income tax benefit expense Deferred Income Tax Expense (Benefit) Condensed Cash Flow Statements, Captions [Line Items] Condensed Cash Flow Statements, Captions [Line Items] Consulting and outside services Consulting Fees Consulting fees other than legal and accounting fees. Available-for-Sale, Amortized Cost Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract] Deposits Interest Expense, Deposits Financial assets Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Loans Held For Sale Loans Held For Sale [Member] This item represents loans held-for-sale including, but not limited to, mortgage loans and finance receivables. Credit quality indictors for HTM debt securities Debt Securities, Held-to-maturity, Credit Quality Indicator [Table Text Block] Retirement Plan Employee Age [Axis] Retirement Plan Employee Age [Axis] Information about age of employee for determination of maximum annual contributions per employee. Federal statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Mergers and acquisition expenses Business Combination, Integration Related Costs Scheduled maturities of time deposits Scheduled Maturities of Certificates of Deposit [Table Text Block] Scheduled maturities of certificates of deposit. Net decrease in short-term Federal Home Loan Bank advances Proceeds from (Repayments of) Short-term Debt, Maturing in Three Months or Less Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Minimum period past due to consider loans as non accrual Minimum Period Past Due To Consider Loans As Non Accrual Minimum Period Past Due To Consider Loans As Non Accrual Net Income Net Income Net income Net Income (Loss) Attributable to Parent Well capitalized requirement, ratio Banking Regulation, Tier One Risk-Based Capital Ratio, Well Capitalized, Minimum Operating lease, net ROU assets Operating Lease, Right-of-Use Asset Non-interest bearing deposits Noninterest-bearing Deposit Liabilities Net operating loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards Income Statement Location [Axis] Income Statement Location [Axis] Parent Holding Company Information (Condensed) Condensed Financial Information of Parent Company Only Disclosure [Text Block] Accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Range [Domain] Statistical Measurement [Domain] Tax-exempt interest income Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent Available-for-sale Debt Securities, Available-for-sale, Realized Gain (Loss) [Abstract] Maximum term leases will be considered short-term Maximum Term Leases Will Be Considered Short-term Maximum Term Leases Will Be Considered Short-term Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Paid-in capital Additional Paid in Capital, Common Stock Employee expenses Miscellaneous Employee Expenses Miscellaneous employee expenses other than compensation and benefits. Finance Leases Finance Lease, Liability, Payment, Due, Rolling Maturity [Abstract] Mortgage-backed securities Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, without Single Maturity Date Retirement Benefits [Abstract] Retirement Benefits [Abstract] Entity File Number Entity File Number Standard & Poor's, A+, A or A- Ratings Standard & Poor's, A+, A or A- Ratings [Member] A+, A or A- credit ratings as defined by the external credit rating agency, Standard & Poor's. Business development Business Development Condensed Balance Sheet Statements, Captions [Line Items] Condensed Balance Sheet Statements, Captions [Line Items] Accounting and audit fees Accounting Fees Accounting Fees Retirement Plan Name [Domain] Retirement Plan Name [Domain] Due after ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value Glacier Capital Trust IV Glacier Capital Trust IV [Member] Glacier Capital Trust IV Deposits with related parties Related Party Deposit Liabilities Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Other Other [Member] Other Available-For-Sale and Transferred Securities: OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax [Abstract] Amortization of investments in variable interest entities Variable Interest Entities Investment Amortization Amount of amortization expense of investment in variable interest entities. Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Variable lease cost Variable Lease, Cost Financial Asset, Past Due Financial Asset, Past Due [Member] Employee benefits Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table] Schedule of Marketable Securities [Table] Schedule of Marketable Securities [Table] Schedule of Marketable Securities [Table] Office Buildings Buildings and construction in progress Building [Member] Net income Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Provision for credit losses Financing Receivable, Credit Loss, Expense (Reversal) Telephone Telephone Expenses Telephone expenses Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Fair value of units that vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Debt Instruments [Abstract] Debt Instruments [Abstract] Maturities, prepayments and calls of available-for-sale debt securities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Net of tax amount OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Assets Assets Assets [Abstract] Accumulated impairment charge Goodwill, Impaired, Accumulated Impairment Loss Land Land [Member] Other Liabilities Other Liabilities [Member] State and local governments US States and Political Subdivisions Debt Securities [Member] Derivatives and Hedging Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Proceeds from sales and calls of debt securities Proceeds From Sales And Calls Of Debt Securities, Available-For-sale Proceeds From Sales And Calls Of Debt Securities, Available-For-sale Other Intangible Assets and Goodwill Goodwill and Intangible Assets Disclosure [Text Block] Premises and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Available-for-sale debt securities Deferred Tax Liabilities, Other Comprehensive Income Beginning balance (in shares) Ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Carrying value of equity investments in LIHTCs Amortization Method Qualified Affordable Housing Project Investments Debt Instrument [Axis] Debt Instrument [Axis] Revolving loans Financing Receivable, Excluding Accrued Interest, Revolving Available-for-sale Debt Securities, Available-for-sale [Abstract] Advertising and Promotion Advertising Cost [Policy Text Block] Financing Receivables, Period Past Due [Domain] Financial Asset, Aging [Domain] Commitments and Contingent Liabilities Commitments and Contingencies Disclosure [Text Block] Well capitalized requirement, ratio Tier One Common Capital Required To Be Well Capitalized To Risk Weighted Assets The Tier 1 common capital ratio (Tier 1 common capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action. Allowance for credit losses Balance at beginning of period Balance at end of period Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest Percentage of employee's contribution required to determine the matched amount under the plan Percentage of Employees Contribution Required to Determine Matched Amount Under Plan Percentage of employee's contribution required to determine matched amount under plan. Right-of-use assets obtained in exchange for operating lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Unaudited Pro Forma Summary of the Acquisitions Business Acquisition, Pro Forma Information [Table Text Block] Summary of net deferred tax asset Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Summary of debt securities Gain (Loss) on Securities [Line Items] Supplemental Disclosure of Non-Cash Investing Activities Other Noncash Investing and Financing Items [Abstract] Minimum period past due to consider loans as delinquent Minimum Period Past Due To Consider Loans As Delinquent Minimum Period Past Due To Consider Loans As Delinquent Proceeds from loans held for sale Proceeds from Sale of Mortgage Loans Held-for-sale Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Additional unfunded commitments on TDRs Additional Outstanding Commitments on Troubled Debt Restructuring Additional outstanding commitments on TDRs. Number of operating segments Number of Operating Segments Total before mortgage-backed securities Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date Total identifiable net assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Number of loans Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts Cost of plan Defined Contribution Plan, Cost Restricted Stock Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Core deposit intangibles Core deposit Intangible Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Loss on early payment of FHLB advances Gain (Loss) on Contract Termination Operating lease, operating cash flows Operating Lease, Payments State Bank of Arizona State Bank of Arizona [Member] State Bank of Arizona Financial Instrument Performance Status [Domain] Financial Instrument Performance Status [Domain] Overdraft demand deposits reclassified as loans Overdraft Demand Deposits Reclassified as Loans Overdraft demand deposits reclassified as loans. Total fair value of consideration transferred Fair value of consideration transferred Business Combination, Consideration Transferred Non-Interest Income Noninterest Income [Abstract] Due within one year Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling within One Year Proceeds from sale of other real estate owned Proceeds from Sale of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans Goodwill Roll Forward Goodwill [Roll Forward] Proceeds from calls of debt securities Held-To-Maturity Securities, Gross Realized Gains (Losses), Sale Proceeds The total amount of proceeds received for the sale of securities categorized as held-to-maturity during the reporting period. The sale of held-to-maturity securities includes proceeds from maturities, prepayments and calls. Mortgage servicing rights Deferred Tax Liabilities, Mortgage Servicing Rights Finance lease, net ROU assets Finance Lease, Right-of-Use Asset, after Accumulated Amortization Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Total assets measured at fair value on a recurring basis Assets, Fair Value Disclosure Net interest income after provision for credit losses Interest Income (Expense), after Provision for Loan Loss Summary of consolidated income tax expense Income Tax Expense (Benefit), Continuing Operations [Abstract] Financial liabilities Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Total liabilities and stockholders’ equity Liabilities and Equity Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Well capitalized requirement, amount Banking Regulation, Tier One Risk-Based Capital, Well Capitalized, Minimum One Year Prior Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Operating Loss and Tax Credit Carryforwards Operating Loss and Tax Credit Carryforwards [Line Items] [Line Items] for Operating Loss and Tax Credit Carryforwards [Table] Net of tax amount Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Residential Real Estate Residential Real Estate [Member] Other Expenses Other Income and Expenses [Abstract] Total Qualified Affordable Housing Project Investments, Commitment 401(k) and Profit Sharing Plans Defined Benefit Plan, Expected Future Employer Contributions [Abstract] Exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Due after five years through ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value Restricted Stock Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] U.S. government and federal agency State and local governments US Government Agencies Debt Securities [Member] Gross realized gains Held-To-Maturity Securities, Sold Security, Realized Gain This item represents the gain realized on the sale of held-to-maturity securities disposed of during the period. Total intrinsic value of options exercised, tax benefit Share-based Payment Arrangement, Exercise of Option, Tax Benefit Interest rate swap derivative financial instruments Derivative [Line Items] General Business Description and Basis of Presentation [Text Block] Held-to-maturity Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract] Actual, ratio Banking Regulation, Tier One Leverage Capital Ratio, Actual Earnings Per Share Earnings Per Share [Text Block] Retirement Plan Employee Age [Domain] Retirement Plan Employee Age [Domain] [Domain] for Information about age of employee for determination of maximum annual contributions per employee. Minimum Range Minimum [Member] Net change in other assets and other liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Income before income tax benefit and equity in undistributed net income of subsidiaries Earnings Before Income Tax Benefit and Equity in Undistributed Earnings of Subsidiaries Earnings before income tax benefit and equity in undistributed earnings of subsidiaries. Commercial loans Interest and Fee Income, Loans, Commercial Preferred shares authorized (in shares) Preferred Stock, Shares Authorized Held-to-Maturity, Amortized Cost Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity [Abstract] Banking and Thrift, Interest [Abstract] Net deferred origination (fees) costs included in loans receivable Unamortized Loan Origination Fees And Costs Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases. Cumulative Effect, Period of Adoption [Axis] Cumulative Effect, Period of Adoption [Axis] 12 months or more, fair value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer Moody's, Not Rated Moody's, Not Rated [Member] Not rated by the external credit rating agency, Moody's. Percentage of outstanding common stock acquired Business Acquisition, Percentage of Voting Interests Acquired Minimum capital requirement, ratio Tier One Common Capital Required For Capital Adequacy To Risk Weighted Assets The minimum Tier One Common Capital Ratio (Tier one common capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. Revenue Recognition Revenue [Policy Text Block] Net cash received from acquisitions Payments to Acquire Businesses, Net of Cash Acquired Borrowings Debt Disclosure [Text Block] Summary of consolidated income tax expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Due within one year Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value Provision for credit loss unfunded Off-Balance Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal) Stock-based Compensation Plan Share-based Payment Arrangement [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Cash dividends paid Payments of Ordinary Dividends, Common Stock Lessee Leases Lessee, Leases [Policy Text Block] Quantitative Information About Level 3 Fair Value Measurements Fair Value Measurement Inputs and Valuation Techniques [Line Items] Premises and equipment, net Net premises and equipment Property, Plant, And Equipment And Lease Right Of Use Asset, After Accumulated Depreciation And Amortization Property, Plant, And Equipment And Lease Right Of Use Asset, After Accumulated Depreciation And Amortization Investment in subsidiaries Investments In Subsidiaries Investments In Subsidiaries 30-89 Days Past Due Nonperforming Financial Instruments 30-89 Days Past Due [Member] Category status of financial instruments in which payments are 30-89 days past due in accordance with the terms of the contract. Financial instruments include, but are not limited to, financing receivables, loans, debt, and investments. Pro Forma Information Business Acquisition, Pro Forma Information [Abstract] Acquisitions and adjustments Goodwill recognized Goodwill, Acquired During Period Financial Asset, Not Past Due Financial Asset, Not Past Due [Member] Commitments and Contingent Liabilities Commitments and Contingencies Loans Receivable Loans and Leases Receivable Disclosure [Abstract] Bank of the San Juans Bancorporation Trust I Bank of the San Juans Bancorporation Trust I [Member] Bank of the San Juans Bancorporation Trust I Accumulated other comprehensive income Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Emerging Growth Company Entity Emerging Growth Company Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Acquisitions Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase Restricted Stock Units Restricted Stock [Member] ACL on held-to-maturity debt securities Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest Receivables [Abstract] Receivables [Abstract] Available-for-Sale, Fair Value Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract] Colorado COLORADO Standard & Poor's, Not Rated Standard & Poor's, Not Rated [Member] Not rated by the external credit rating agency, Standard & Poor's. Auditor Name Auditor Name Cover [Abstract] Other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Financing Receivable, Credit Quality Indicator [Table] Financing Receivable, Credit Quality Indicator [Table] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Summary of debt securities with an unrealized loss position Schedule of Unrealized Loss on Investments [Table Text Block] Difference between lease payments and present value of lease payments Lessee, Operating Lease, Liability, Undiscounted Excess Amount Doubtful/ Loss Doubtful [Member] Bank-Owned Life Insurance Bank-Owned Life Insurance Policy [Policy Text Block] Bank-Owned Life Insurance Policy Condensed Statements of Cash Flows Condensed Cash Flow Statement [Table Text Block] Tax effect OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax Financial Instrument [Axis] Financial Instrument [Axis] Number of shares issued for acquisition (in shares) Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Debt securities, available-for-sale Fair Value Fair Value Debt Securities, Available-for-Sale, Excluding Accrued Interest Number of years before allowed to prepay Tier 2 subordinated debt Number Of Years Before Allowed To Prepay Debt Number Of Years Before Allowed To Prepay Debt Difference between lease payments and present value of lease payments Finance Lease, Liability, Undiscounted Excess Amount Proceeds from bank-owned life insurance Proceeds from Life Insurance Policy Current Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Carrying Amount Reported Value Measurement [Member] Outstanding commitments Other Commitments [Abstract] Gross Unrealized Losses Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss Common Stock Common Stock [Member] Leasehold improvements Building Improvements [Member] Company's contribution to the plan Defined Contribution Plan, Employer Discretionary Contribution Amount Supplemental Employee Retirement Plan Supplemental Employee Retirement Plans [Member] Supplemental Employee Retirement Plans [Member] Short-term Operating Lease, Liability, Current Financing Receivables, Period Past Due [Axis] Financial Asset, Aging [Axis] Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Nature of Operations and Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] 2023 Finite-Lived Intangible Asset, Expected Amortization, Year Two Minimum capital requirement, amount Banking Regulation, Common Equity Tier One Risk-Based Capital, Capital Adequacy, Minimum Stock-based compensation, net of tax benefits Stock-based compensation, net of tax benefits Share-based Payment Arrangement, Noncash Expense First Company Statutory Trust 2001 First Company Statutory Trust 2001 [Member] First Company Statutory Trust 2001 AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Purchases of available-for-sale debt securities Payments to Acquire Debt Securities, Available-for-sale Number of loans Financing Receivable, Modifications, Number of Contracts Provision for credit losses on debt securities Debt Securities, Available-for-sale, Change in Present Value, Expense (Reversal) Cash paid during the period for income taxes Income Taxes Paid Securities pledged for repurchase agreements Pledged Financial Instruments, Not Separately Reported, Securities for Repurchase Agreements Total debt securities Debt Securities, Available-for-Sale and Held-to-Maturity, after Allowance for Credit Loss [Abstract] Minimum number of hours required to be considered eligible for employer discretionary contribution Minimum Number Of Hours Required To Be Considered Eligible For Employer Discretionary Contribution Minimum Number of Hours Required to be Considered Eligible for Employer Discretionary Contribution of the Profit Sharing Plan. Loans Held for Sale Financing Receivable, Held-for-sale [Policy Text Block] Legal fees Legal Fees Fair value of common stock shares issued Stock Issued Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Amortization expense Amortization Method Qualified Affordable Housing Project Investments, Amortization Repayments of long-term Federal Home Loan Bank advances Payments of FHLBank Borrowings, Financing Activities Total liabilities Liabilities Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Net purchase accounting (discounts) premiums included in loans receivable Unamortized Discounts And Premiums On Loans Amount of premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Principal balances of loans serviced for others Servicing Asset 2022 Finite-Lived Intangible Asset, Expected Amortization, Year One Aggregate intrinsic value of outstanding stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Acquisitions Noncash or Part Noncash Acquisition, Net Nonmonetary Assets Acquired (Liabilities Assumed) [Abstract] Measurement Input Type [Axis] Measurement Input Type [Axis] Operating loss carryforwards, amount Operating Loss Carryforwards Debt securities pledged as collateral Security Owned and Pledged as Collateral, Fair Value Preferred shares issued (in shares) Preferred Stock, Shares Issued Recognized amounts of identifiable assets acquired and liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract] Debt securities, held-to-maturity Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss Due within one year Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value Entity Address, City or Town Entity Address, City or Town Future Unfunded Contingent Commitments Qualified Affordable Housing Project Investments Commitment [Table Text Block] Tabular disclosure of information about Qualified Affordable Housing Project Investments Commitments. Gross realized losses Debt Securities, Available-for-sale, Realized Loss Other Borrowings Consolidation, Variable Interest Entity, Policy [Policy Text Block] Activity within Accumulated Other Comprehensive Income (Loss), Net of Tax Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Performing Performing Financial Instruments [Member] Liability related to obligations of deferred compensation plans Deferred Compensation Arrangement with Individual, Recorded Liability Postage Postage Expense Balance Sheet Location [Axis] Balance Sheet Location [Axis] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] FNB (UT) Statutory Trust I FNBUTStatutoryTrustIMember [Member] FNB (UT) Statutory Trust I Fair Value, Measurement Frequency [Domain] Measurement Frequency [Domain] Capital conservation buffer CapitalConservationBufferToRiskWeightedAssetsCurrentYear Capital Conservation Buffer as a percentage of risk-weighted assets required for the current year. Total interest expense Interest expense Interest Expense Deferred Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Total interest income Interest income Interest and Dividend Income, Operating Rate Debt Instrument, Interest Rate, Effective Percentage Accruing loans 60-89 days past due Financial Asset, 60 to 89 Days Past Due [Member] Data processing Information Technology and Data Processing 401(k) and Profit Sharing Plan Defined Contribution Plan [Member] Defined Contribution Plan [Member] Retained earnings - substantially restricted Retained earnings Retained Earnings (Accumulated Deficit) Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Recoveries Financing Receivable, Allowance for Credit Loss, Recovery Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Amortization expense and tax credits and other tax benefits recognized for qualified affordable housing project investments Equity Method Investments [Table Text Block] Entity Filer Category Entity Filer Category Summary of Pre-Tax Gains or Losses Derivative Instruments, Gain (Loss) [Table Text Block] Estimated Fair Value Estimate of Fair Value Measurement [Member] TDR with pre modification loan balance for which oreo was received TDR With Pre Modification Loan Balance For Which Oreo Was Received TDR with pre modification loan balance, for which OREO was received. Deferred loan costs Deferred Tax Liabilities, Tax Deferred Income Held-to-Maturity Debt Securities, Held-to-maturity, Maturity [Abstract] Other Expenses [Abstract] Other Expenses [Abstract] Other assets Other Noncurrent Assets [Member] Proceeds from stock option exercises Proceeds from Stock Options Exercised Maturing three years through four years Finance Lease, Liability, Payments, Due in Rolling Year Four Due after ten years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years Derivative, term of contract Derivative, Term of Contract Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] OREO Secured by Residential Real Estate Real Estate Acquired Through Foreclosure, Secured By Residential Real Estate Real Estate Acquired Through Foreclosure, Secured By Residential Real Estate Amendment Flag Amendment Flag Other Commercial Commercial Portfolio Segment [Member] Statement, Equity Components [Axis] Equity Components [Axis] Term deposits Deposits, Fair Value Disclosure Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Condensed Statements of Operations and Comprehensive Income Statement of Operations [Abstract] Statement of operations. Maturities of Lease Liabilities Lessee Lease Liability Maturity [Table Text Block] Tabular disclosure of undiscounted cash flows of lessee's operating and finance lease liabilities. Includes, but is not limited to, reconciliation of undiscounted cash flows to operating and finance lease liabilities recognized in statement of financial position. (Losses) Gains on Derivatives Used for Cash Flow Hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Federal Deferred Federal Income Tax Expense (Benefit) Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures [Abstract] Mortgage-backed securities Debt Securities, Held-to-maturity, Maturity, without Single Maturity Date, Fair Value Fair Value Option, Disclosures [Table] Fair Value Option, Disclosures [Table] Preferred shares, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Entity Public Float Entity Public Float Documents Incorporated by Reference Documents Incorporated by Reference [Text Block] Short-term lease cost Short-term Lease, Cost FDIC Insurance limit Cash, FDIC Insured Amount PCD loans acquired Financing Receivable, Purchased with Credit Deterioration, Amount at Par Value Net additions to premises and equipment Net additions of premises and equipment Payments for (Proceeds from) Productive Assets Statement [Line Items] Statement [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Actual, ratio Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Actual Loss on termination of hedging activities Loss On Hedging Activity Loss incurred in hedging activities. Credit quality indicators for commercial loans Financing Receivable Credit Quality Indicators [Table Text Block] Equity Securities Equity Securities [Policy Text Block] Equity Securities [Policy Text Block] Weighted- Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Service charges and other fees Service Charges And Other Fees Service Charges and Other Fees on Deposit Accounts. Debt securities, available-for-sale Debt Securities, Available-for-sale Off-balance sheet commitments Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability Debt Disclosure [Abstract] Debt Disclosure [Abstract] Moody's, A1, A2 or A3 Ratings Moody's, A1, A2 or A3 Ratings [Member] A1, A2 or A3 credit ratings as defined by the external credit rating agency, Moody's. Business assets Business Assets [Member] Business Assets Non-Interest Expense Noninterest Expense [Abstract] Subordinated Debentures Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Text Block] Junior subordinated debenture owed to unconsolidated subsidiary trust. Property, Plant and Equipment by Type [Axis] Long-Lived Tangible Asset [Axis] Deferred tax assets, valuation allowance Deferred Tax Assets, Valuation Allowance Home Equity Home Equity Portfolio Segment [Member] Portfolio segment of the company's total financing receivables related to home equity loans. Tier 1 capital (to average assets) Banking Regulation, Tier One Leverage Capital [Abstract] Minimum capital requirement, amount Banking Regulation, Tier One Risk-Based Capital, Capital Adequacy, Minimum Finance lease cost Finance Lease Liability [Abstract] Minimum capital requirement, ratio Banking Regulation, Total Risk-Based Capital Ratio, Capital Adequacy, Minimum Actual, ratio Banking Regulation, Tier One Risk-Based Capital Ratio, Actual Terms of Subordinated Debentures Terms of Subordinated Debentures Abstract Terms of subordinated debentures. Total before mortgage-backed securities Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Fair Value Employee Benefit Plans Retirement Benefits [Text Block] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Fair Value by Asset Class [Axis] Asset Class [Axis] Document Annual Report Document Annual Report Interest receivable, available-for-sale debt securities Interest receivable, available-for-sale debt securities Carrying amount as of the balance sheet date of interest earned but not received on available-for-sale debt securities. Period past due to consider loans as delinquent Period Past Due to Consider Loans as Delinquent Period Past Due to Consider Loans as Delinquent Total assets Assets Proceeds from redemption of non-marketable equity securities Proceeds from Sale of Federal Home Loan Bank Stock Summary of Loans Receivable Loan portfolio aging analysis Financing Receivable, after Allowance for Credit Loss [Abstract] Changes in fair value, gains (losses) Fair Value, Option, Changes in Fair Value, Gain (Loss) Cash paid during the period for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Loans receivable, net of ACL Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Receivable Parent Company Parent Company [Member] Previous Acquisitions Prior Year Acquisitions [Member] Consists of all acquisitions occurring during the prior year. Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Summary of loans receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Derivative, Name [Domain] Derivative Contract [Domain] Charge-offs Financing Receivable, Allowance for Credit Loss, Writeoff Maximum number of consecutive quarters for deferral of interest payments on trust preferred securities Maximum Number Of Consecutive Quarters For Deferral Of Interest Payments On Trust Preferred Securities Maximum Number Of Consecutive Quarters For Deferral Of Interest Payments On Trust Preferred Securities Subordinated debentures Subordinated Debt Obligations, Fair Value Disclosure Cumulative Effect, Period of Adoption [Domain] Cumulative Effect, Period of Adoption [Domain] Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Furniture, Fixtures and Equipment Furniture and Fixtures [Member] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Maturing two years through three years Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Three Residential Real Estate Residential Portfolio Segment [Member] Average outstanding shares - basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted earnings per share (in dollars per share) Earnings Per Share, Diluted Repayment of notes receivable from related parties Repayment of Notes Receivable from Related Parties 2022 Qualified Affordable Housing Project Investments, Commitment To Be Paid Year One Qualified Affordable Housing Project Investments, Commitment To Be Paid Year One Federal Home Loan Bank advances Interest Expense Federal Home Loan Bank Advance Interest expense federal home loan bank advance. Lease Expense Lease, Cost [Abstract] Total Comprehensive Income Comprehensive Income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Unaudited Quarterly Financial Data (Condensed) Quarterly Financial Information [Text Block] Well capitalized requirement, amount Banking Regulation, Common Equity Tier One Risk-Based Capital, Well Capitalized, Minimum Accrued interest receivable on loans Interest Receivable, Financing Receivable Carrying amount as of the balance sheet date of interest earned but not received on financing receivable. Letters of credit Letters of Credit [Member] An irrevocable undertaking (typically by a financial institution) to guarantee payment of a specified financial obligation. Debt Securities Schedule of Marketable Securities [Line Items] [Line Items] for Schedule of Marketable Securities [Table] [Table] Deferred tax liability Deferred Income Tax Liabilities, Net Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Summary of effective tax rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Consolidated VIEs Variable Interest Entity, Primary Beneficiary [Member] Current Year Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year Age of employee Defined Contribution Plan Age Of Employee Employee age threshold for determination of maximum annual contributions per employee. Collateral Held [Axis] Collateral Held [Axis] Borrowings Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Borrowings Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Borrowings. Percentage of consolidated stockholders equity exceeding which no borrower had outstanding loans or commitments Percentage of Consolidated Stockholders Equity Exceeding Which no Borrower had Outstanding Loans or Commitments Percentage of consolidated stockholders equity exceeding which no borrower had outstanding loans or commitments. Fair value measurement of assets and liabilities measured at fair value on a recurring basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Carrying amounts of consolidated VIEs' assets and liabilities Schedule of Variable Interest Entities [Table Text Block] Accumulated Other Comp-rehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Bank-owned life insurance Bank Owned Life Insurance Other assets Other Assets Additions Servicing Asset at Amortized Cost, Additions Number of common stock shares issued and outstanding (in shares) Balance (in shares) Balance (in shares) Common Stock, Shares, Outstanding Financial Instruments [Domain] Financial Instruments [Domain] Depreciation and amortization of premises and equipment Depreciation, Nonproduction Summarized unaudited quarterly financial data Selected Quarterly Financial Information [Abstract] Stock issuances under stock incentive plans (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Provision for credit losses Total provision for credit losses Provision for Loan, Lease, and Other Losses Entity Central Index Key Entity Central Index Key Interest rate caps Interest Rate Cap [Member] Non-accrual loans with ACL Financing Receivable Nonaccrual With Allowance Amount of financing receivable on nonaccrual status with allowance for credit loss. Actual, amount Banking Regulation, Total Capital, Actual Total lease expense Lease, Cost Principal collected on loans Proceeds from Loan and Lease Originations and Principal Collections Schedule of Financing Receivables Past Due [Table] Financing Receivable, Past Due [Table] Maturing four years through five years Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Five Consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are in process Mortgage Loans in Process of Foreclosure, Amount ACL on available-for-sale debt securities Debt Securities, Available-for-Sale, Amortized Cost, Allowance for Credit Loss, Excluding Accrued Interest Premises and Equipment Property, Plant and Equipment Disclosure [Text Block] Actual, ratio Banking Regulation, Total Risk-Based Capital Ratio, Actual Held-to-Maturity, Fair Value Debt Securities, Held-to-maturity, Maturity, Fair Value, Rolling Maturity [Abstract] Residential mortgage-backed securities Residential Mortgage Backed Securities [Member] Condensed Financial Information Disclosure [Abstract] Condensed Financial Information Disclosure [Abstract] Derivative asset, fair value, gross liability Derivative Asset, Fair Value, Gross Liability Loans held for sale, at fair value Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance Debt Instrument [Line Items] Debt Instrument [Line Items] Gross Unrealized Gains Securities, Gross Unrealized Gain Accumulated In Investments Amount of accumulated unrealized gain before deducting unrealized loss on investments in available-for-sale and held-to-maturity securities impacting investments. Trading Symbol Trading Symbol Interest rate caps Derivative Asset Net interest income and non-interest income Business Acquisition, Pro Forma Revenue Other Deferred Tax Liabilities, Other Total, unrealized loss Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss Net decrease (increase) in other assets Increase (Decrease) in Other Operating Assets Subordinated debentures Balance Subordinated Debt Securities sold under agreements to repurchase Interest Expense, Securities Sold under Agreements to Repurchase Condensed Income Statements, Captions [Line Items] Condensed Income Statements, Captions [Line Items] Well capitalized requirement, amount Banking Regulation, Tier One Leverage Capital, Well Capitalized, Minimum Actual, amount Banking Regulation, Tier One Leverage Capital, Actual Sales of available-for-sale debt securities Proceeds from Sale of Debt Securities, Available-for-sale Subordinated debentures owed to trust subsidiaries Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Member] Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Member] Deposits [Abstract] Deposits [Abstract] Lessor Leases Lessor, Leases [Policy Text Block] Impact of adopting CECL Financing Receivable, Change in Method, Credit Loss Expense (Reversal) Non-accrual loans with no ACL Financing Receivable, Nonaccrual, No Allowance Moody's, Aaa Rating Moody's, Aaa Rating [Member] Compensation expense related to stock-based compensation plans Share-based Payment Arrangement, Expense Cost Approach Valuation, Cost Approach [Member] Employee Benefit Plans Defined Contribution Plan Disclosure [Line Items] 2023 Time Deposit Maturities, Year Two Compensation and employee benefits Labor and Related Expense U.S. government sponsored enterprises U.S. government sponsored enterprises US Government-sponsored Enterprises Debt Securities [Member] Total liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Prior Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year Credit quality indicators for RRE and consumer loans Financing Receivable Credit Quality Indicators 2 [Table Text Block] Tabular disclosure of financing receivables by credit quality indicator. The credit quality indicator is a statistic about the credit quality of financing receivables. Examples include, but not limited to, consumer credit risk scores, credit-rating-agency ratings, an entity's internal credit risk grades, loan-to-value ratios, collateral, collection experience and other internal metrics. Cash, cash equivalents and restricted cash at beginning of period Cash, cash equivalents and restricted cash at end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Purchases of non-marketable equity securities Payments to Acquire Federal Home Loan Bank Stock Transfer of loans to other real estate owned Real Estate Owned, Transfer to Real Estate Owned ACL on PCD loans acquired Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share (Loss) gain on sale of debt securities Debt Securities, Realized Gain (Loss) Maturing one year through two years Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Two Purchases of held-to-maturity debt securities Payments to Acquire Held-to-maturity Securities Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Gross carrying value Finite-Lived Intangible Assets, Gross Internal Investment Grade Internal Investment Grade [Member] Loans receivable acquired, gross principal and contractual interest due Business Combination, Acquired Receivables, Gross Contractual Amount Net Core Deposit Intangibles and Aggregate Amortization Expense Finite-Lived Intangible Assets, Net [Abstract] Summary of core deposit intangibles Schedule of Finite-Lived Intangible Assets [Table Text Block] Long-lived Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Condensed Balance Sheet Statement [Table] Condensed Balance Sheet Statement [Table] Federal Internal Revenue Service (IRS) [Member] Unrealized (losses) gains on available-for-sale securities OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax Standard & Poor's, AA+, AA or AA- Ratings Standard & Poor's, AA+, AA or AA- Ratings [Member] AA+, AA or AA- credit ratings as defined by the external credit rating agency, Standard & Poor's. External Credit Rating, Standard & Poor's [Domain] External Credit Rating, Standard & Poor's [Domain] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Due after one year through five years Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Total other comprehensive (loss) income, net of tax Other comprehensive (loss) income Other Comprehensive Income (Loss), Net of Tax Recurring measurements Fair Value, Recurring [Member] Liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] Overnight and Continuous Maturity Overnight [Member] Regulatory Capital Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Fair Value Debt Securities, Fair Value Fair value of investments in debt securities classified as available-for sale and held-to-maturity. Loss on termination of interest rate swaps Loss on Derivative Instruments, Pretax Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Cash consideration Cash Consideration For Outstanding Shares Cash Consideration For Outstanding Shares Measurement Basis [Axis] Measurement Basis [Axis] 2026 Finite-Lived Intangible Asset, Expected Amortization, Year Five Total amount deferred Deferred Compensation Arrangement with Individual, Compensation Expense Auditor Firm ID Auditor Firm ID Charge-offs on TDRs Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Investments in Qualified Affordable Housing Projects Investments in Affordable Housing Projects [Abstract] VIE amortization and other expenses VIE Write-Downs, Losses And Other Expenses Write-downs, Losses and Other Expenses related to Variable Interest Entities. Well capitalized requirement, ratio Banking Regulation, Tier One Leverage Capital Ratio, Well Capitalized, Minimum Servicing Asset at Amortized Cost, Balance [Roll Forward] Servicing Asset at Amortized Cost, Balance [Roll Forward] Debt securities, held-to-maturity Amortized Cost Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Cash consideration Payments to Acquire Businesses, Gross Outstanding commitments Other Commitments [Table Text Block] Defined Contribution Plan [Table] Defined Contribution Plan [Table] Lines of credit Line of Credit Facility, Maximum Borrowing Capacity Carrying value at beginning of period Carrying value at end of period Servicing Asset at Amortized Cost Finance lease, operating cash flows Finance Lease, Interest Payment on Liability Proceeds from sale of marketable equity securities Payments for Proceeds from Non Marketable Equity Securities Payments for proceeds from non-marketable equity securities. Three Years Prior Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Amortized cost, gross unrealized gains and losses and the fair value of debt securities Marketable Securities [Table Text Block] Altabank Altabancorp [Member] Altabancorp Loans held for sale, at fair value Loans Held-for-sale, Fair Value Disclosure Advertising and promotions Advertising Expense Prepaid Expenses and Other Current Assets Prepaid Expenses and Other Current Assets [Member] Moody's, Aa1, Aa2 or Aa3 Ratings Moody's, Aa1, Aa2 or Aa3 Ratings [Member] Aa1, Aa2 or Aa3 credit rating as defined by the external credit rating agency, Moody's. Regulatory assessments and insurance General Insurance And Federal Deposit Insurance Corporation Premium Expense The expense in the period incurred with respect to protection provided by insurance entities against risks other than risks associated with production, including the amount of expense for Federal Deposit Insurance Corporation (FDIC) insurance. Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Reclassification adjustment for gains (losses) included in net income Amount of loss reclassified from OCI to interest expense Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Actual, amount Banking Regulation, Tier One Risk-Based Capital, Actual Quantitative information about assets measured at fair value on a non-recurring basis for which Level 3 inputs were used Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Tax credit period Tax Credit Period The period in which an investor receives tax credits from a tax credit project. Interest rate locks Interest Rate Lock Commitments [Member] Common stock, $0.01 par value per share, 117,187,500 shares authorized Common stock Common Stock, Value, Outstanding Citizens (ID) Statutory Trust I Citizens (ID) Statutory Trust I [Member] Citizens (ID) Statutory Trust I Finance lease, ROU assets Finance Lease, Right-of-Use Asset, before Accumulated Amortization Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Other Real Estate Owned Financing Receivable, Held-for-investment, Foreclosed Asset [Policy Text Block]