Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Contractual Principal Financing Receivable, Held-for-Sale Subordinated debentures Subordinated Debt Maximum Maximum [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Federal Income Tax Jurisdiction, Domestic Federal [Member] Loan participations Loan Participations Amount of loan participations with other financial institutions. Title of 12(b) Security Title of 12(b) Security Carrying Value Reported Value Measurement [Member] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-Sale [Table] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Schedule of Assets Measured at Fair Value on a Non-Recurring Basis Fair Value Measurements, Nonrecurring [Table Text Block] Adjustment to Compensation, Amount Adjustment to Compensation Amount Nonaccrual With No Related Allowance Financing Receivable, Nonaccrual, No Allowance Financial Instrument Financial Instrument [Axis] Financing Receivable, Nonaccrual [Table] Financing Receivable, Nonaccrual [Table] Segment Reporting [Abstract] Segment Reporting [Abstract] Schedule of Estimated Amortization Expense for Future Years Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense [Table Text Block] Subordinated Notes Maturing January 2026 Subordinated Notes Maturing January 2026 [Member] Subordinated Notes Maturing January 2026 LEASES Lessee, Finance Leases [Text Block] 2027 Finance Lease, Liability, to be Paid, Year One Derivative Instrument Derivative Instrument [Axis] Investment securities Business Combination, Recognized Asset Acquired, Investment in Debt and Equity Securities, Current Measurement Frequency [Axis] Measurement Frequency [Axis] Junior Subordinated Debentures Junior Subordinated Debt [Member] Accrued interest receivable on loans Financing Receivable, Accrued Interest, before Allowance for Credit Loss Consolidated Entities Consolidated Entities [Axis] Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock, Shares Outstanding Financial Instrument Performance Status Financial Instrument Performance Status [Domain] Par value of acquired loans at acquisition Financing Receivable, Purchased with Credit Deterioration, Amount at Par Value Schedule of Remaining Contractual Maturity of Secured Borrowings and Class of Collateral Pledged Schedule Of Remaining Contractual Maturity Of Secured Borrowings And Class Of Collateral Pledged Under Repurchase Agreements [Table Text Block] Schedule of remaining contractual maturity of secured borrowings and class of collateral pledged under repurchase agreements. QUALIFIED AFFORDABLE HOUSING PROJECTS AND OTHER TAX CREDIT INVESTMENTS Qualified Affordable Housing Projects And Other Tax Credit Investments [Text Block] Qualified affordable housing projects and other tax credit investments. Premises and equipment Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment Doubtful Doubtful [Member] Leases [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Consolidated Entities Consolidated Entities [Domain] Schedule of Held-to-Maturity Investment Securities with Unrecognized Losses Debt Securities, Held-to-Maturity [Table Text Block] Prior Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year, Writeoff Originated more than five years before current fiscal year Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year Common stock, stated value (in dollars per share) Common Stock, Par or Stated Value Per Share Amount Reclassified from AOCI Reclassification out of Accumulated Other Comprehensive Income [Member] Schedule of Activity in Trouble Debt Restructurings Financing Receivable, Modified [Table Text Block] Writeoff, by Origination Year Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Unrecognized Losses Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss [Abstract] Number of reportable operating segment Number of Reportable Segments First Midwest Capital Trust I First Midwest Capital Trust I [Member] First Midwest Capital Trust I Customer relationship Customer Relationships [Member] Available-for-sale, amortized cost Amortized Cost Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss Entity Address, City or Town Entity Address, City or Town Money market Deposits, Money Market Deposits Class of Financing Receivable Class of Financing Receivable [Domain] Receivables [Abstract] Receivables [Abstract] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Customer foreign currency contracts Customer Foreign Exchange Forward [Member] Customer Foreign Exchange Forward Current fiscal year Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year, Writeoff Number of loan portfolios Financing Receivable, Number Of Loan Portfolios Financing Receivable, Number Of Loan Portfolios Other intangible assets Net Carrying Amount Intangible Asset, Finite-Lived, after Accumulated Amortization Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Past Due 90 Days or More Financial Asset, Equal to or Greater than 90 Days Past Due [Member] Forward contract indexed to issuer's equity (in shares) Forward Contract Indexed to Issuer's Equity, Shares UNITED STATES UNITED STATES Old National Bancorp Parent Company [Member] Proceeds from sales of residential real estate loans Proceeds from Sale, Loan, Mortgage, Held-for-Sale Impaired Commercial and Commercial Real Estate Loans Impaired Commercial And Commercial Real Estate Loans [Member] Impaired commercial and commercial real estate loans. Changes from hedges Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Equipment Equipment Expense Loan commitments floating rate, minimum Loan Commitments Floating Interest Rate Minimum Minimum floating rate percentage charged on loan commitments. Cash collateral pledged Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Security Not Offset Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Savings Deposits, Savings Deposits Other comprehensive income (loss), net of tax Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent One to five years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Noncash Investing and Financing Activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Allowance for credit losses on loans Allowance for credit losses on loans Balance at Beginning of Period Balance at End of Period Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest Document Period End Date Document Period End Date Gross amounts not offset in the Consolidated Balance Sheet Derivative Liability, Subject to Master Netting Arrangement, after Offset and Deduction [Abstract] Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Issuance amount Issuance Amount Debt Instrument, Face Amount 2028 Lessee, Operating Lease, Liability, to be Paid, Year Two Revolving to Term Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan Debt assumed Business Combination, Recognized Liability Assumed, Long-Term Debt, Noncurrent Realized losses Debt Securities, Available-for-Sale, Realized Loss Rate Debt Instrument, Interest Rate, Effective Percentage Within one year Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, Year One Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Domain] Beyond ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10 Securities sold under agreements to repurchase Securities sold under agreements to repurchase Outstanding at period end Securities Sold under Agreements to Repurchase Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Finance leases Finance Lease, Weighted Average Remaining Lease Term Accumulated other comprehensive income (loss), net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Unfunded loan commitments Loan Commitments Amount of agreement to extend credit in the form of a loan. Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Total Class of Loans Financing Receivable, Excluding Accrued Interest, Modified in Period, to Total Financing Receivables, Percentage Schedule of Qualified Affordable Housing Projects and Other Tax Credit Investments Investment Holdings, Schedule of Investments [Table Text Block] NET INCOME PER COMMON SHARE Earnings Per Share [Text Block] Earnings Per Share [Abstract] Earnings Per Share [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Within one year Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One Total liabilities Liabilities Trading Symbol Trading Symbol Weighted- Average Interest Rate Reduction Financing Receivable, Modified, Weighted-Average Interest Rate Decrease from Modification Discount for type of property, age of appraisal, and current status Measurement Input, Discount Rate [Member] Commercial real estate Commercial Real Estate Foreclosed Assets [Member] Commercial Real Estate Foreclosed Assets Investment securities - available-for-sale, at fair value (amortized cost $12,605,107 and $12,059,997, respectively) Fair Value Total Debt Securities, Available-for-Sale, Excluding Accrued Interest Purchases of premises and equipment and other assets Payments to Acquire Property, Plant, and Equipment Schedule of Interest Rate Derivatives Schedule of Interest Rate Derivatives [Table Text Block] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Proceeds from Federal Home Loan Bank advances Proceeds from FHLBank Borrowings, Financing Activities Company Selected Measure Name Company Selected Measure Name Purchases of investment securities available-for-sale Payments to Acquire Debt Securities, Available-for-Sale Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Forward mortgage loan contracts Forward Commitments [Member] Forward commitments. Deposits Interest Expense, Deposits Fixed rates Fixed rate Long-Term Debt, Percentage Bearing Fixed Interest, Percentage Rate Unfunded Commitment, Proportional amortization Amortization Method Qualified Affordable Housing Project Investments Commitment Amortization method qualified affordable housing project investments commitment. Term of standby letters of credit, years Term Of Standby Letters Of Credit Length of time that standby letters of credit are effective. One to five years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Weighted average common shares outstanding: Earnings Per Share, Diluted [Abstract] Forward sale agreement Stock Issued During Period, Value, Forward Sale Agreements Stock Issued During Period, Value, Forward Sale Agreements Financial Instrument Performance Status Financial Instrument Performance Status [Axis] Depositary Shares, each representing a 1/40th interest in a share of Non-Cumulative Perpetual Preferred Stock, Series C Depositary Shares, each representing a 1/40th interest in a share of Non-Cumulative Perpetual Preferred Stock, Series C [Member] Depositary Shares, each representing a 1/40th interest in a share of Non-Cumulative Perpetual Preferred Stock, Series C Schedule of Derivatives not Designated as Hedging Instruments Derivatives Not Designated as Hedging Instruments [Table Text Block] Originated in current fiscal year Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year Cash Flows From Operating Activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Nonaccrual Amortized Cost Financing Receivable, Nonaccrual Other borrowings Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Borrowings Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Borrowings St. Joseph Capital Trust II St Joseph Capital Trust II [Member] St Joseph Capital Trust Ii. Beyond ten years Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity, after Year 10 Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] 2028 Finance Lease, Liability, to be Paid, Year Two Thereafter Finite-Lived Intangible Asset, Expected Amortization, After Year Four Finite-Lived Intangible Asset, Expected Amortization, After Year Four 2030 Finance Lease, Liability, to be Paid, Year Four U.S. Treasury U.S. Treasury U.S. Treasury and agency securities US Treasury Securities [Member] Operating loss carryforwards Operating Loss Carryforwards Entities [Table] Entities [Table] Expected tax deductible amount Business Combination, Goodwill, Expected Tax Deductible, Amount Total Debt Securities, Held-to-Maturity, Unrealized Loss Position, Accumulated Loss Residential Residential Foreclosed Assets [Member] Residential foreclosed assets. Amounts representing interest Finance Lease, Liability, Undiscounted Excess Amount Unfunded commitments on TDRs Financing Receivable, Modified, Commitment to Lend Wealth and investment services fees Fees And Commission Fiduciary And Trust Activities Fees and commission fiduciary and trust activities. Operating cash flows from operating leases Operating Lease, Payments Award Timing Predetermined Award Timing Predetermined [Flag] Loan placed on nonaccrual when past due, number of days Finance Receivable Past Due Period For Nonaccrual Status Maximum number of days past due before loan is placed on nonaccrual status. Great Lakes Statutory Trust II Great Lakes Statutory Trust II [Member] Great Lakes Statutory Trust II Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Share-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Loan originations and payments, net Payments for (Proceeds from) Loans and Leases, Excluding Loans Held-For-Sale Payments for (Proceeds from) Loans and Leases, Excluding Loans Held-For-Sale Federal Home Loan Bank advances Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Federal Home Loan Bank Advances Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Federal Home Loan Bank Advances Effective tax rate Effective Income Tax Rate Reconciliation, Percent Schedule of Financing Receivable, Purchased with Credit Deterioration Financing Receivable, Purchased With Credit Deterioration [Table Text Block] Financing Receivable, Purchased With Credit Deterioration Anchor Capital Trust III Anchor Capital Trust I I I [Member] Anchor Capital Trust III. Maximum amount outstanding at any month-end during the period Short-Term Debt, Maximum Month-end Outstanding Amount Restricted stock (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Proceeds from sales of equity securities Proceeds from Sale, Debt Security, Trading, and Equity Security, FV-NI, Held-for-Investment Summary of Investment Holdings [Line Items] Summary of Investment Holdings [Line Items] Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value [Table] Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table] Off-Balance Sheet, Credit Loss, Liability [Roll Forward] Off-Balance-Sheet, Credit Loss, Liability [Roll Forward] Class of Financing Receivable Class of Financing Receivable [Axis] OTHER BORROWINGS Other Liabilities Disclosure [Text Block] Depreciation Depreciation Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Cancellable loan commitments Cancellable Loan Commitments Cancellable Loan Commitments Leveraged loans for NMTC (fixed rates of 1.00% to 7.25%) maturing December 2027 to June 2061 Notes Payable to Bank Within one year Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Counterparty foreign currency contracts Counterparty Foreign Exchange Forward [Member] Counterparty Foreign Exchange Forward Debt Instrument, Name Debt Instrument, Name [Domain] Auto Automobiles [Member] INVESTMENT SECURITIES Investment in Debt and Equity Securities and Other Trading Assets [Text Block] Standby letters of credit Long-Term Line of Credit Reclassification, Type [Domain] Reclassification, Type [Domain] Cash dividends paid Payments of Ordinary Dividends, Common Stock Expiration Date Trading Arrangement Expiration Date Due in 2030 Long-Term Debt, Maturity, Year Four Hedging Relationship [Axis] Hedging Relationship [Axis] Portfolio Segment Reclassifications Segment Portfolio Reclassification [Member] Segment Portfolio Reclassification Unrealized Gains Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain Offsetting derivative positions Derivative Asset, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset Federal Historic Tax Credit (“FHTC”) Federal Historic Tax Credits [Member] Federal historic tax credits. Net credit exposure Derivative Asset, Subject to Master Netting Arrangement, after Offset and Deduction Federal Home Loan Bank, Advances [Table] Federal Home Loan Bank, Advances [Table] Allowance Established for Acquired PCD Loans Financing Receivable, Excluding Accrued Interest, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date Loan participations retained Loan Participations Retained Amount of loan participations retained. Subordinated Debt Subordinated Debt [Member] Available-for-sale, Amortized Cost Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Amortized Cost [Abstract] Cash dividends: Dividends [Abstract] Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Derivative [Table] Derivative [Table] Forward contrac indexed to issuers equity, period granted to purchase additional shares (in days) Forward Contract Indexed To Issuers Equity, Period Granted To Purchase Additional Shares Forward Contract Indexed To Issuers Equity, Period Granted To Purchase Additional Shares Difference  Fair Value, Option, Aggregate Differences, Loans and Long-Term Receivables Cash Flows From Investing Activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Investment Investments In Qualified Affordable Housing Projects Investments in qualified affordable housing projects. Proceeds Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale Assets Derivative Asset [Abstract] Interest Rate Swap Interest Rate Swap [Member] Leveraged loans, compliance period (in years) Leveraged Loans, Compliance Period Leveraged Loans, Compliance Period Additional number of shares (in shares) Forward Contract Indexed to Issuer's Equity, Additional Number of Shares Forward Contract Indexed to Issuer's Equity, Additional Number of Shares Transaction costs, expensed Business Combination, Acquisition And Integration Related Costs Business Combination, Acquisition And Integration Related Costs Business Combination [Table] Business Combination [Table] ACQUISITION AND DIVESTITURE ACTIVITY Mergers, Acquisitions and Dispositions Disclosures [Text Block] Loans including fees: Interest and Fee Income, Financing Receivable [Abstract] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Cash Flows [Extensible Enumeration] Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Cash Flows [Extensible Enumeration] Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Loans held-for-sale, at fair value Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance Finance leases Finance Lease, Weighted Average Discount Rate, Percent Interest rate Debt Instrument, Interest Rate, Stated Percentage Total shareholders’ equity Beginning balance Ending balance Equity, Attributable to Parent Other assets Business Combination, Recognized Asset Acquired, Other Asset, Noncurrent Securities or Other Assets Sold under Agreements to Repurchase Securities or Other Assets Sold under Agreements to Repurchase [Axis] Assets Assets [Abstract] Due in 2029 Federal Home Loan Bank, Advance, Maturity, Year Three Direct Finance Leases Finance Leases Portfolio Segment [Member] Payment Delay Payment Deferral [Member] Issuance of common stock shares for acquisitions of business (in shares) Business Combination, Consideration Transferred, Equity Interest, Share Issued, Number of Shares Allowance for credit losses at acquisition Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date Schedule of Risk Category of Loans and Amortized Cost Financing Receivable Credit Quality Indicators [Table Text Block] Fair Value on Non-recurring Basis Fair Value, Nonrecurring [Member] Professional fees Professional Fees Insider Trading Policies and Procedures [Line Items] Nonperforming Nonperforming Financial Instruments [Member] Interest rate swaps on borrowings Variable Interest Rate Swap, Borrowings [Member] Variable Interest Rate Swap, Borrowings Debit card and ATM fees Debit Card And Atm Fees The noninterest income derived from debit card and ATM fees. Commercial real estate Commercial real estate loans Commercial Real Estate Portfolio Segment [Member] Financing Receivable Portfolio Segment Financing Receivable Portfolio Segment [Domain] New Markets Tax Credit (“NMTC”) New Markets Tax Credit [Member] New Markets Tax Credit Schedule of Changes in Carrying Amount of Goodwill Goodwill [Table Text Block] Entity Central Index Key Entity Central Index Key Net interest income after provision for credit losses Interest Income (Expense), after Provision for Loan Loss Capital surplus Additional Paid in Capital, Common Stock Equity [Abstract] Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Low Income Housing Tax Credit (“LIHTC”) Low Income Housing Tax Credits [Member] Low income housing tax credits. Provision at statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Due in 2026 Long-Term Debt, Maturity, Remainder of Fiscal Year Weighted- Average Payment Delay (in months) Financing Receivable, Modified, Payment Deferral, Period Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Finance lease, right-of-use asset, statement of financial position [extensible enumeration] Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Purchase price of loans at acquisition Purchase price of loans at acquisition Financing Receivable, Purchased with Credit Deterioration, Amount at Purchase Price Available-for-sale, Weighted Average Yield Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity [Abstract] Variable rate Debt Instrument, Basis Spread on Variable Rate Total undiscounted lease payments Finance Lease, Liability, to be Paid Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Federal funds purchased and interbank borrowings Interest Expense, Federal Funds Purchased All Individuals All Individuals [Member] Bridgeview Capital Trust II Bridgeview Capital Trust II [Member] Bridgeview Capital Trust II Due in 2030 Federal Home Loan Bank, Advance, Maturity, Year Four Performing Performing Financial Instruments [Member] Income tax effect OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), Tax Statement [Line Items] Statement [Line Items] Total assets Assets Operating Leases Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Term Extension Extended Maturity [Member] Total interest expense Interest Expense, Operating Internal Credit Assessment Internal Credit Assessment [Domain] Assets Sold under Agreements to Repurchase [Line Items] Assets Sold under Agreements to Repurchase [Line Items] Reclassification adjustment for securities (gains) losses realized in income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Equity securities without readily determinable fair value Equity Securities without Readily Determinable Fair Value, Amount Schedule of Assets Sold under Agreements to Repurchase [Table] Asset Sold under Agreement to Repurchase [Table] Weighted-Average Discount Rate Lessee Weighted Average Discount Rate [Abstract] Lessee, weighted-average discount rate. Unrealized Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Total liabilities Business Combination, Recognized Liability Assumed, Liability Impairment charges Intangible Asset, Excluding Goodwill, Indefinite-Lived, Impairment Loss Other comprehensive income (loss) before reclassifications OCI, before Reclassifications, Net of Tax, Attributable to Parent Occupancy Occupancy, Net PEO PEO [Member] Due in 2028 Long-Term Debt, Maturity, Year Two Other borrowings Interest Expense, Other Long-Term Debt Goodwill Balance at beginning of period Balance at end of period Goodwill Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Monroe Bancorp Capital    Trust I Monroe Bancorp Capital Trust I [Member] Monroe Bancorp Capital Trust I. Number of securities in unrealized loss position Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Offsetting derivative positions Derivative Liability, Subject to Master Netting Arrangement, Deduction of Financial Instrument Not Offset FHLB/Federal Reserve Bank stock Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, FHLB/Federal Reserve Bank Stock Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, FHLB/Federal Reserve Bank Stock Retained Earnings Retained Earnings [Member] Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Schedule of Carrying Amounts and Estimated Fair Values of Financial Instruments, Not Carried at Fair Value Fair Value, by Balance Sheet Grouping [Table Text Block] Financing Receivable, Past Due [Line Items] Financing Receivable, Past Due [Line Items] Net income per common share - diluted (in dollars per share) Diluted Net Income Per Common Share (in dollars per share) Earnings Per Share, Diluted Internal Credit Assessment Internal Credit Assessment [Axis] FDIC assessment Federal Deposit Insurance Corporation Premium Expense Amortization of intangibles Amortization of other intangible assets Intangible Asset, Finite-Lived, Amortization Expense Intangible Asset, Finite-Lived [Line Items] Intangible Asset, Finite-Lived [Line Items] Weighted-average rates of FHLB advances Federal Home Loan Bank, Advances, Activity for Year, Average Interest Rate at Period End Foreclosed Assets Foreclosed Assets [Member] Foreclosed Assets Originated three years before current year Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year Finance lease cost: Finance Lease Costs [Abstract] Finance lease costs. Schedule of Offsetting Assets Offsetting Assets [Table Text Block] Total assets Business Combination, Recognized Asset Acquired, Asset Past due period of mortgage loans held for sale, days Past Due Period Of Mortgage Loans Held For Sale Number of days past due in relation to loans held for sale. Financial Assets Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Common stock repurchased Stock Repurchased During Period, Value Investment, Proportional Amortization Method, Elected, Statement of Financial Position [Extensible Enumeration] Investment, Proportional Amortization Method, Elected, Statement of Financial Position [Extensible Enumeration] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Schedule of Composition of Loans and Impact of Adoption Accounting Standards Update and Change in Accounting Principle [Table Text Block] Principal amount of impaired commercial and commercial real estate loans Principal Amount Of Commercial And Commercial Real Estate Loans Principal amount of impaired commercial and commercial real estate loans. Proceeds from Sale, Maturity and Collection of Investments [Abstract] Proceeds from Sale, Maturity and Collection of Investments [Abstract] State income taxes Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Schedule of Contractual Maturities of Other Borrowings Schedule of Maturities of Long-Term Debt [Table Text Block] Gain (Loss) Recognized in Income on Derivative Derivative, Gain (Loss) on Derivative, Net Citibank, N.A Citibank, N.A [Member] Citibank, N.A Nontaxable or nondeductible items: Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount [Abstract] 2026 Finance Lease, Liability, to be Paid, Remainder of Fiscal Year Hedge gain to be reclassified to interest expense during next twelve months, net Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified To Interest Expense During Next 12 Months, Net Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified To Interest Expense During Next 12 Months, Net Change in hedges: Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract] Interest rate swaps on investment securities Variable Interest Rate Swap, Available-For-Sale Investment Securities [Member] Variable Interest Rate Swap, Available-For-Sale Investment Securities Federal Home Loan Bank, Advances [Line Items] Federal Home Loan Bank, Advances [Line Items] Percentage of risk-based capital Commercial Real Estate Loans As Percentage Of Risk Based Capital Commercial real estate loans as a percentage of risk-based capital. Basis adjustments Debt Securities, Available-For-Sale, Accumulated Basis Adjustments, Before Tax Debt Securities, Available-For-Sale, Accumulated Basis Adjustments, Before Tax Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Pooled trust preferred securities Pooled Trust Preferred Securities [Member] Pooled trust preferred securities. Carrying value of letters of credit Carrying Value Of Letter Of Credit Carrying value of standby letters of credit financial instruments. Revolving Financing Receivable, Excluding Accrued Interest, Revolving Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Schedule of Activity in Allowance for Loan Losses Financing Receivable, Allowance for Credit Loss [Table Text Block] Common stock, shares issued (in shares) Common Stock, Shares, Issued Entity Information [Line Items] Entity Information [Line Items] Available-for-Sale, 12 months or longer, Unrealized Losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) Comprehensive Income (Loss) Note [Text Block] FEDERAL HOME LOAN BANK ADVANCES Federal Home Loan Bank Advances, Disclosure [Text Block] Noninterest Expense Noninterest Expense [Abstract] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Payment defaults Financing Receivable, Modified, Subsequent Default Marketing Marketing and Advertising Expense 2029 Lessee, Operating Lease, Liability, to be Paid, Year Three Within one year Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity, Year One Termination Date Trading Arrangement Termination Date Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Other intangible assets Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Finite-Lived Financial Assets Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] U.S. government-sponsored entities and agencies U.S. government-sponsored entities and agencies US Government-sponsored Enterprises Debt Securities [Member] First Midwest First Midwest Bancorp, Inc. [Member] First Midwest Bancorp, Inc. Fair Value as of Grant Date Award Grant Date Fair Value Schedule of Available-for-Sale and Held-to-Maturity Investment Securities with Unrealized Losses by Aggregated Major Security Type and Length of Time in Continuous Unrealized Loss Position Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Schedule of Goodwill [Table] Goodwill [Table] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Arrangement Duration Trading Arrangement Duration BBCC Business Banking Credit Center Portfolio Segment [Member] Business Banking Credit Center Portfolio Segment Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Available-for-Sale, Less than 12 months, Unrealized Losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Repurchase Agreements and Similar Transactions, Maturity Periods Repurchase Agreements and Similar Transactions, Maturity Periods [Domain] Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Gross Carrying Amount Intangible Asset, Finite-Lived, before Accumulated Amortization Tax-exempt interest Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Renewable Energy Renewable Energy Program [Member] Additional number of shares to purchase (in shares) Forward Contract Indexed to Issuer's Equity, Additional Number of Shares To Purchase Forward Contract Indexed to Issuer's Equity, Additional Number of Shares To Purchase Amortization of right-of-use assets Finance Lease, Right-of-Use Asset, Amortization Citigroup Global Markets Inc. Citigroup Global Markets Inc. [Member] Citigroup Global Markets Inc. Loan Restructuring Modification [Axis] Loan Restructuring Modification [Axis] Goodwill [Roll Forward] Goodwill [Roll Forward] Intangible Asset, Finite-Lived, Class Intangible Asset, Finite-Lived, Class [Domain] Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] All Award Types Award Type [Domain] Interest on lease liabilities Finance Lease, Interest Expense Fair Value Option, Disclosures [Table] Fair Value Option, Disclosures [Table] 2026 Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year FAIR VALUE Fair Value Disclosures [Text Block] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Held-to-Maturity, Amortized Cost Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date [Abstract] 2027 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year One Customer and offsetting counterparty derivative instruments Customer And Offsetting Counterparty Derivative Instruments [Member] Customer And Offsetting Counterparty Derivative Instruments Operating lease term Lessee, Operating Lease, Term of Contract Share price (in dollars per share) Share Price Allowance for securities held-to-maturity Allowance for securities held-to-maturity Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest Other borrowings Proceeds from (Repayments of) Other Debt 30-59 Days Past Due Financial Asset, 30 to 59 Days Past Due [Member] Legal Entity Legal Entity [Axis] Up to 30 Days Maturity Less than 30 Days [Member] Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Noninterest Income Noninterest Income [Abstract] Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Schedule of Finite-Lived Intangible Assets [Table] Intangible Asset, Finite-Lived [Table] New market tax credits Effective Income Tax Rate Reconciliation, New Market Tax Credits, Amount Effective Income Tax Rate Reconciliation, New Market Tax Credits, Amount Unfunded Commitment, Equity Equity Method Qualified Affordable Housing Project Investments Commitment Equity method qualified affordable housing project investments commitment. Schedule of Reclassifications out of AOCI Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Non-NEOs Non-NEOs [Member] Financing Receivable, Allowance for Credit Loss [Roll Forward] Financing Receivable, Allowance for Credit Loss [Roll Forward] Overnight and Continuous Maturity Overnight [Member] Cash Payments to Acquire Businesses, Gross 2028 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Two Held-to-Maturity, Fair Value Debt Securities, Held-to-Maturity, Fair Value, Maturity [Abstract] Net amount presented in the Consolidated Balance Sheet Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral LEASES Lessee, Operating Leases [Text Block] Due in 2027 Long-Term Debt, Maturity, Year One Long-term Debt, Type Long-Term Debt, Type [Domain] Five to ten years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Schedule of Supplemental Balance Sheet Information Related to Leases Schedule Of Supplemental Balance Sheet Information Related To Leases [Table Text Block] Schedule of supplemental balance sheet information related to leases. Common stock repurchased Payments for Repurchase of Common Stock Checking, NOW, savings, and money market    interest-bearing deposits Checking Now Savings And Money Market Interestbearing Deposits Checking, NOW, savings, and money market interest-bearing deposits. Mortgage-backed securities - Agency Collateralized Mortgage-Backed Securities [Member] Statistical Measurement Statistical Measurement [Axis] FHLB advances (fixed rates 3.34% to 4.86%    and variable rates 3.75% to 4.03%) maturing   November 2026 to March 2046 Long-Term Federal Home Loan Bank Advances Award Type Award Type [Axis] Net unrealized derivative gains (losses) on hedges Gain (Loss) Recognized in Other Comprehensive Income on Derivative Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax Interest rate contracts Interest Rate Contract [Member] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Real Estate Real Estate [Member] Hedge gain to be reclassified to interest income during next twelve months, net Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified To Interest Income During Next 12 Months, Net Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified To Interest Income During Next 12 Months, Net Assets Sold under Agreements to Repurchase, Type Assets Sold under Agreements to Repurchase, Type [Domain] Retained earnings Retained Earnings (Accumulated Deficit) Consumer Consumer Consumer credit Consumer Portfolio Segment [Member] Change in securities held-to-maturity: Other Comprehensive Loss, Held-to-Maturity Security, OTTI, after Tax and Adjustments, Attributable to Parent [Abstract] Old National Bank Old National Bank [Member] Old national bank. Investment Holdings [Table] Investment Holdings [Table] Securities sold under agreements to repurchase Interest Expense, Securities Sold under Agreements to Repurchase Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Common Stock Common Stock [Member] Investment securities available-for-sale: Debt Securities, Available-for-Sale Modifications, unamortized prepayment fees Advances From Federal Home Loan Banks, Modifications, Unamortized Prepayment Fees Advances From Federal Home Loan Banks, Modifications, Unamortized Prepayment Fees Realignment of Loan Portfolio Segments Financing Receivable, Allowance for Credit Loss, Realignment Of Loan Portfolio Segments Financing Receivable, Allowance for Credit Loss, Realignment Of Loan Portfolio Segments Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Operating lease cost Operating Lease, Cost Four years before current fiscal year Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff Interest-bearing: Deposits, by Type [Abstract] Derivative Contract Derivative Contract [Domain] Forward contract indexed to equity, settlement, cash Forward Contract Indexed to Equity, Settlement, Cash, Amount Other Gains and (Losses) Other Nonoperating Gains (Losses) Total Past Due Financial Asset, Past Due [Member] Number of loan segments Financing Receivable, Number Of Loan Segments Financing Receivable, Number Of Loan Segments Total liabilities and shareholders’ equity Liabilities and Equity Employee Stock Option Share-Based Payment Arrangement, Option [Member] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Asset Class Asset Class [Axis] Equity securities Business Combination, Recognized Asset Acquired, Investment in Equity Securities Business Combination, Recognized Asset Acquired, Investment in Equity Securities Tabular List, Table Tabular List [Table Text Block] Percent of unfunded loan commitments with fixed rates Percent Of Unfunded Loan Commitments With Fixed Rates Percent Of Unfunded Loan Commitments With Fixed Rates Leveraged Loans for NMTC Notes Payable to Banks [Member] Common stock issued for ESPP Proceeds From Issuance Of Common Stock For ESPP Proceeds From Issuance Of Common Stock For ESPP 2029 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Three 2026 remaining Intangible Asset, Finite-Lived, Estimated Amortization Expense, Remainder of Fiscal Year Name Awards Close in Time to MNPI Disclosures, Individual Name Five to ten years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 5 through 10 Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Financing Receivable Portfolio Segment Financing Receivable Portfolio Segment [Axis] Operating Leases Lessee Operating Leases [Abstract] Lessee, operating leases. Preferred stock, 2,000 shares authorized, 231 shares issued and outstanding Preferred Stock, Value, Issued Adjustment to Compensation: Adjustment to Compensation [Axis] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Total interest paid Interest Paid, Excluding Capitalized Interest, Operating Activity Hedging Designation Hedging Designation [Axis] 60-89 Days Past Due Financial Asset, 60 to 89 Days Past Due [Member] Fair Value Assets, Fair Value Disclosure Name Measure Name Investment Securities/Cash Investment Securities And Cash Collateral [Member] Investment Securities And Cash Collateral Purchases of Federal Home Loan Bank/Federal Reserve Bank stock Payments to Acquire Restricted Investments Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Domain] Commitments to extend credit Fair Value Disclosure, off-Balance-Sheet Risks, Amount, Liability Debt Instrument [Line Items] Debt Instrument [Line Items] Taxable Interest and Fee Income, Financing Receivable Junior subordinated debentures (rates of 5.56% to 7.66%) maturing July 2031 to September 2037 Junior Subordinated Notes Capital Surplus Additional Paid-in Capital [Member] Five to ten years Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 5 Through 10 Goodwill impairment Goodwill, Impairment Loss Interest Income Interest and Fee Income, Financing Receivable, Held-in-Portfolio [Abstract] Accrued interest receivable Interest Receivable Name Trading Arrangement, Individual Name Northern States Statutory Trust I Northern States Statutory Trust I [Member] Northern States Statutory Trust I Total cash and cash equivalents Cash, due from banks, money market,    and other interest-earning investments Cash and Cash Equivalent Blanket Lien Blanket Lien Collateral [Member] Blanket Lien Collateral Debt securities gains (losses), net Debt securities (gains) losses, net Debt securities gains (losses), net Debt and Equity Securities, Gain (Loss) Company Selected Measure Amount Company Selected Measure Amount (Losses) gains on equity securities Equity Securities, FV-NI, Unrealized Gain (Loss) Net (discount accretion) premium amortization Investment Income, Net, Amortization of Discount and Premium Fair value hedge basis adjustments and unamortized prepayment fees Fair value hedge basis adjustments and unamortized prepayment fees Advances From Federal Home Loan Banks, Fair Value Hedge Basis adjustments And Unamortized Prepayment Fees Advances From Federal Home Loan Banks, Fair Value Hedge Basis adjustments And Unamortized Prepayment Fees Operating leases Operating Lease, Weighted Average Remaining Lease Term Stock activity under incentive compensation plans Shares Issued, Value, Share-Based Payment Arrangement, Including Stock Dividends Shares Issued, Value, Share-Based Payment Arrangement, Including Stock Dividends Non-PEO NEO Non-PEO NEO [Member] Noninterest-bearing demand Noninterest-bearing demand deposits Noninterest-Bearing Deposit Liabilities, Domestic Total noninterest expense Noninterest Expense Gain (Loss) Recognized in Income on Related Hedged Items Gain (Loss) on Fair Value Hedges Recognized in Earnings Award Timing Method Award Timing Method [Text Block] Net increase (decrease) in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] SECURITIES SOLD UNDER AGREEMENTS TO REPURCHASE Transfers and Servicing of Financial Assets [Text Block] Accrued interest receivable Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss Net income Net income Net income Net income Net Income (Loss) Attributable to Parent Long-term Debt, Type Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Proceeds from sales of premises and equipment and other assets Proceeds from Sale of Property, Plant, and Equipment Financing Receivable, Past Due [Table] Financing Receivable, Past Due [Table] Restatement Determination Date: Restatement Determination Date [Axis] Schedule of AOCI Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Liabilities Business Combination, Recognized Liability Assumed, Liability [Abstract] Federal Home Loan Banks [Abstract] Federal Home Loan Banks [Abstract] Thereafter Federal Home Loan Bank, Advance, Maturity, after Year Four Federal Home Loan Bank, Advance, Maturity, after Year Four Federal funds purchased and interbank borrowings Federal Funds Purchased Bremer Statutory Trust II Bremer Statutory Trust II [Member] Bremer Statutory Trust II Provision for credit losses on unfunded loan commitments acquired during the period Off-Balance Sheet, Credit Loss, Liability, Acquired Loans Off-Balance Sheet, Credit Loss, Liability, Acquired Loans Total Changes in Fair Values Included in Current Period Earnings Fair Value, Option, Changes in Fair Value, Gain (Loss) Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Beyond ten years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 10 Income tax effect OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, Tax Statistical Measurement Statistical Measurement [Domain] Forward Contract Indexed to Issuer's Equity, Type [Axis] Forward Contract Indexed to Issuer's Equity, Type [Axis] Document Fiscal Year Focus Document Fiscal Year Focus Less: amounts offset in the Consolidated Balance Sheet Derivative Liability, Subject to Master Netting Arrangement, Asset Offset Common stock issued for forward sale agreements Proceeds From Issuance Of Common stock For Forward Sale Agreements Proceeds From Issuance Of Common stock For Forward Sale Agreements Transferred from available-for-sale to held-for-maturity Transfers From Available-for-Sale to Held-to-Maturity Transfers From Available-for-Sale to Held-to-Maturity Standby letters of credit Notional Amount Of Standby Letters Of Credit Amount of agreement to extend credit in the form of a standby letter of credit. Total deposits Deposits Common stock, no par value, $1.00 per share stated value, 600,000 shares authorized,    378,639 and 389,662 shares issued and outstanding, respectively Common Stock, Value, Issued Interest (Expense) Interest Expense, Operating and Nonoperating 2027 Lessee, Operating Lease, Liability, to be Paid, Year One Due in 2028 Federal Home Loan Bank, Advance, Maturity, Year Two Schedule of Other Borrowings Schedule of Loan Commitments Schedule of Long-Term Debt Instruments [Table Text Block] Schedule of FHLB Advances Federal Home Loan Bank, Advances [Table Text Block] Communication Communication Restatement Determination Date Restatement Determination Date Tax Jurisdiction of Domicile [Extensible Enumeration] Tax Jurisdiction of Domicile [Extensible Enumeration] Off-Balance Sheet Financial Instruments Fair Value Disclosure, off-Balance-Sheet Risks, Amount [Abstract] Fair Value Disclosure, off-Balance-Sheet Risks, Amount Federal Home Loan Bank advances Interest Expense, Federal Home Loan Bank and Federal Reserve Bank Advances, Long-Term Depositary Shares, each representing a 1/40th interest in a share of Non-Cumulative Perpetual Preferred Stock, Series A Depositary Shares, each representing a 1/40th interest in a share of Non-Cumulative Perpetual Preferred Stock, Series A [Member] Depositary Shares, each representing a 1/40th interest in a share of Non-Cumulative Perpetual Preferred Stock, Series A Schedule of Differences in Taxes from Continuing Operations Computed at Statutory Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Other expense Other Noninterest Expense Service charges on deposit accounts Fees And Commissions Depositor Account Fees And commissions depositor account. Amendment Flag Amendment Flag Goodwill [Line Items] Goodwill [Line Items] Finance Leases Lessee Finance Leases [Abstract] Lessee, finance leases. Schedule of Trading Securities and Other Trading Assets [Line Items] Debt and Equity Securities, FV-NI [Line Items] Financing cash flows from finance leases Finance Lease, Principal Payments Unrealized Losses Available-for-Sale, Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Schedule of Amortized Cost and Fair Value of Available-for-Sale and Held-to-Maturity Investment Securities Portfolio Debt Securities, Available-for-Sale [Table Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Investments Investments [Domain] Residential real estate loans originated for sale Payment for Origination, Loan, Mortgage, Held-for-Sale FHLB Advances Federal Home Loan Bank Advances [Member] Federal Home Loan Bank/Federal Reserve Bank stock, at cost Federal Home Loan Bank Stock and Federal Reserve Bank Stock Weighted-average interest rate during year Short-Term Debt, Weighted Average Interest Rate, over Time Acquisition of Bremer Financial Corporation Common stock issued for merger, net Common stock (50,183 shares issued at $20.59 per share) Stock Issued During Period, Value, Acquisitions Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Tower Capital Trust 3 Tower Capital Trust Three [Member] Tower Capital Trust Three [Member] Entity Address, State or Province Entity Address, State or Province Purchases of equity securities Payments to Acquire Equity Securities, FV-NI PEO Total Compensation Amount PEO Total Compensation Amount Tax credit investments - federal: Effective Income Tax Rate Reconciliation, Tax Credit, Amount [Abstract] Investment, Proportional amortization Investment, Proportional Amortization Method, Elected, Amount Financial Liabilities Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract] Notional amount Notional Derivative, Notional Amount Weighted average number of common shares outstanding - basic (in shares) Weighted average common shares outstanding (basic) (in shares) Weighted Average Number of Shares Outstanding, Basic Loan commitments floating rate, maximum Loan Commitments Floating Interest Rate Maximum Maximum floating rate percentage charged on loan commitments. Loss Contingencies [Line Items] Loss Contingencies [Line Items] 2030 Lessee, Operating Lease, Liability, to be Paid, Year Four Financing Receivable, Credit Quality Indicator [Line Items] Financing Receivable, Credit Quality Indicator [Line Items] Money market and other interest-earning investments Interest-Bearing Deposits in Banks and Other Financial Institutions Unfunded Loan Commitment Unfunded Loan Commitment [Member] Five to ten years Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Schedule of Maturity Analysis of Lease Liability by Lease Classification Schedule Of Maturities Of Operating And Finance Leases Liabilities [Table Text Block] Schedule of maturities of operating and finance leases liabilities. (Increase) decrease in interest receivable Increase (Decrease) in Accrued Interest Receivable, Net Change in debt securities available-for-sale: Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent [Abstract] Total noninterest income Noninterest Income Thereafter Lessee, Operating Lease, Liability, To Be Paid, After Year Four Lessee, Operating Lease, Liability, To Be Paid, After Year Four LOANS AND ALLOWANCE FOR CREDIT LOSSES Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Fair value of consideration Business Combination, Consideration Transferred [Abstract] Time deposits Time deposits Time Deposits Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Class of Stock Class of Stock [Axis] Net income applicable to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Debt Securities, Held-to-Maturity [Table] Debt Securities, Held-to-Maturity [Table] Accumulated Amortization and Impairment Intangible Asset, Finite-Lived, Accumulated Amortization Sub-lease income Sublease Income Preferred Dividends, Preferred Stock Net loans Loans, net Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Monroe Bancorp Statutory    Trust II Monroe Bancorp Statutory Trust II [Member] Monroe Bancorp Statutory Trust Ii. Cash paid for amounts included in the measurement of lease liabilities: Cash Paid For Amounts Included In Measurement Of Lease Liabilities Lessee [Abstract] Cash paid for amounts included in measurement of lease liabilities, lessee. Schedule of Derivative Instruments Effect on Consolidated Statement of Income Schedule Of Derivative Instruments Effect On Consolidated Statement Of Income [Table Text Block] Tabular disclosure of effect of derivative instruments on the consolidated income statement.  30-90 Days Maturity 30 to 90 Days [Member] Originated two years before current year Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year Less than 12 months Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Net cash flows provided by (used in) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Five to ten years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Loans, net of allowance for credit losses Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loan Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loan Security Exchange Name Security Exchange Name Amortized Cost Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss Regulatory guideline limit Commercial Real Estate Loans As Percentage Of Risk Based Capital Regulatory Guide Line Limit The regulatory guideline limit for commercial real estate loans as a percentage of risk-based capital. Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Income or Comprehensive Income [Extensible Enumeration] Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization, Statement of Income or Comprehensive Income [Extensible Enumeration] Schedule of Contractual Maturities of FHLB Advances Schedule Of Federal Home Loan Bank Advances Maturities [Table Text Block] Schedule of federal home loan bank advances maturities. One to five years Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year One through Five Changes from securities held-to-maturity Other Comprehensive Loss, Held-to-Maturity Security, OTTI, Excluding Transfers, after Tax and Adjustments, Attributable to Parent Other Comprehensive Loss, Held-to-Maturity Security, OTTI, Excluding Transfers, after Tax and Adjustments, Attributable to Parent Accrued interest receivable and other assets Interest Receivable and Other Assets Available-for-Sale, 12 months or longer, Fair Value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Premises and equipment, net Finance Lease, Right-of-Use Asset, after Accumulated Amortization Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Proceeds from sales of Federal Home Loan Bank/Federal Reserve Bank stock Proceeds from Sale of Restricted Investments Name Outstanding Recovery, Individual Name Net increase (decrease) in: Increase (Decrease) In Deposits and Debt [Abstract] Increase (Decrease) In Deposits and Debt Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Cash collateral pledged Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Security Not Offset Impairments on equity securities without readily determinable fair value Equity Securities without Readily Determinable Fair Value, Impairment Loss, Annual Amount Held-to-Maturity Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity [Abstract] Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] One to five years Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity, after Year One Through Five Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Amounts reclassified from AOCI to income Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Effect of dilutive securities: Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract] Reclassification, Type [Axis] Reclassification, Type [Axis] Cash per share above exchange (in dollars per share) Business Acquisition, Equity Interest Issued Or Issuable, Cash Per Share Above Exchange Business Acquisition, Equity Interest Issued Or Issuable, Cash Per Share Above Exchange Total Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value Within one year Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Unrealized gains (losses) on available-for-sale securities OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax Asset Class Asset Class [Domain] Payments for maturities of Federal Home Loan Bank advances Payments of FHLBank Borrowings, Financing Activities Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Weighted average number of common shares outstanding - diluted (in shares) Weighted average diluted shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Entity Emerging Growth Company Entity Emerging Growth Company Total loans, net of unearned income Total loans Total loans Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss Underlying Security Market Price Change Underlying Security Market Price Change, Percent Premises and equipment, net Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization DERIVATIVE FINANCIAL INSTRUMENTS Derivative Instruments and Hedging Activities Disclosure [Text Block] Unrealized Losses Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss Income Taxes [Table] Income Taxes [Table] Income Taxes [Table] Amounts representing interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration] Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration] Gross amounts recognized Derivative liabilities Derivative Liability, Subject to Master Netting Arrangement, before Offset Provision (release) for credit losses on unfunded loan commitments Off-Balance-Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal) Loans: Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss [Abstract] Intangible Asset, Goodwill and Other [Abstract] Intangible Asset, Goodwill and Other [Abstract] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Interest Rate Reduction Interest Rate Below Market Reduction [Member] Total undiscounted lease payments Lessee, Operating Lease, Liability, to be Paid Schedule of Difference Between the Aggregate Fair Value and the Aggregate Remaining Principal Balance Fair Value Option, Disclosures [Table Text Block] Two years before current fiscal year Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff All Executive Categories All Executive Categories [Member] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Interest rate lock commitments Interest Rate Lock Commitments [Member] Weighted-average interest rate: Short-Term Debt, Weighted Average Interest Rate [Abstract] Short-Term Debt, Weighted Average Interest Rate Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Deposits Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Deposits Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Deposits Provision for Loan Losses Financing Receivable, Credit Loss, Expense (Reversal), Excluding Held-to-Maturity Securities Financing Receivable, Credit Loss, Expense (Reversal), Excluding Held-to-Maturity Securities Accounting Changes and Error Corrections [Abstract] Accounting Changes and Error Corrections [Abstract] Technology Information Technology and Data Processing Loans held-for-sale Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Held-For-Sale Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Held-For-Sale Schedule of Basic and Diluted Net Income Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Thereafter Long-Term Debt, Maturity, After Year Four Long-Term Debt, Maturity, After Year Four SEGMENT INFORMATION Segment Reporting [Text Block] Proceeds from maturities, prepayments, and 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[Extensible Enumeration] Business Combination [Line Items] Business Combination [Line Items] Common Dividends, Common Stock Other income Noninterest Income, Other Operating Income Financing Receivable, Allowance for Credit Loss [Table] Financing Receivable, Allowance for Credit Loss [Table] Authorized and unissued common shares reserved for issuance (in shares) Common Stock, Shares Authorized Estimated useful lives Intangible Asset, Finite-Lived, Useful Life Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Other real estate owned property write-downs Other Real Estate Owned Property Write Down Amount of write downs on foreclosed assets measured on a non-recurring basis during the period, including other real estate owned and other repossessed property. 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Foreign currency contracts Foreign Exchange Contract [Member] Adoption Date Trading Arrangement Adoption Date Other basis adjustments Other Basis Adjustments Other basis adjustments. Trust Preferred Securities Trust Preferred Securities [Member] Trust preferred securities. Equity securities, at fair value Equity securities Equity Securities, FV-NI, Current Percentage of periodic changes in fair value qualifies for hedge accounting treatment Percentage Of Periodic Changes In Fair Value Qualifies For Hedge Accounting Percentage of periodic changes in fair value qualifies for hedge accounting. 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All Adjustments to Compensation All Adjustments to Compensation [Member] Core deposit Core Deposits [Member] Business Combination Business Combination [Axis] Net cash flows provided by (used in) operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Residential real estate Residential real estate Residential Residential Portfolio Segment [Member] Indirect Indirect Portfolio Segment [Member] Indirect Portfolio Segment Substandard Substandard [Member] Money market and other interest-earning investments Interest Income, Deposits with Financial Institutions Income Statement [Abstract] Income Statement [Abstract] Shareholders’ Equity Equity, Attributable to Parent [Abstract] Initiatives in Low-to-Moderate Income Neighborhoods Initiatives in Low-to-Moderate Income Neighborhoods [Member] Initiatives in Low-to-Moderate Income Neighborhoods Document Transition Report Document Transition Report Fair Value, Option, Quantitative Disclosures [Line Items] Fair Value, Option, Quantitative Disclosures [Line Items] Finance lease, liability, statement of financial position [extensible enumeration] Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Schedule of Gross Carrying Amounts and Accumulated Amortization of Other Intangible Assets Intangible Asset, Finite-Lived [Table Text Block] Beyond ten years Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year 10 City Area Code City Area Code Home Federal Statutory    Trust I Home Federal Statutory Trust I [Member] Home Federal Statutory Trust I. Name Forgone Recovery, Individual Name Due in 2026 Federal Home Loan Bank, Advance, Maturity, Remainder of Fiscal Year Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Total Available For Sale Securities Debt Maturities Weighted Average Yield Weighted average yield on total available-for-sale securities. Entity Entity [Domain] Federal funds purchased and interbank borrowings Increase (Decrease) in Federal Funds Purchased Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Total interest income Interest and Dividend Income, Operating Financing Receivable, Credit Quality Indicator [Table] Financing Receivable, Credit Quality Indicator [Table] Past Due 90 Days or More and Accruing Financing Receivable, 90 Days or More Past Due, Still Accruing Thereafter Finance Lease, Liability, To Be Paid, After Year Four Finance Lease, Liability, To Be Paid, After Year Four Loans held-for-sale Aggregate Fair Value Loan, Mortgage, Held-for-Sale, Fair Value Disclosure Common stock issued for Employee Stock Purchase Plan (“ESPP”) Stock Issued During Period, Value, Employee Stock Purchase Plan (Increase) decrease in other assets Increase (Decrease) in Other Operating Assets Great Lakes Statutory Trust III Great Lakes Statutory Trust III [Member] Great Lakes Statutory Trust III Gross amounts not offset in the Consolidated Balance Sheet Derivative Asset, Subject to Master Netting Arrangement, after Offset and Deduction [Abstract] Measurement Basis [Axis] Measurement Basis [Axis] Less: amounts offset in the Consolidated Balance Sheet Derivative Asset, Subject to Master Netting Arrangement, Liability Offset Proceeds from sales of commercial loans Proceeds from Sale, Loan, Held-for-Investment Acquisitions and adjustments Goodwill, Acquired During Period Unrealized holding gains (losses) for the period OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment and Tax Within one year Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Bridgeview Statutory Trust I Bridgeview Statutory Trust I [Member] Bridgeview Statutory Trust I Unrealized Gains and Losses on Available-for-Sale Debt Securities Unrealized gains and losses on    available-for-sale securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] Cash and cash equivalents Business Combination, Recognized Asset Acquired, Cash and Cash Equivalent Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Schedule of Quantitative Information about Significant Unobservable Inputs Used in Fair Value Measurements Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Other consumer Other Consumer Segment [Member] Other Consumer Segment Entity Current Reporting Status Entity Current Reporting Status Net cash flows provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Mortgage banking revenue Fees and Commissions, Mortgage Banking and Servicing Income tax effect Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax Allowance for unfunded loan commitments Allowance For Unfunded Loan Commitments Amount of valuation allowance recorded for unfunded commitments to extend credit. Cash flow hedges: Cash Flow Hedging [Member] Other Other Collateral [Member] Other Collateral Schedule of Assets Acquired and Liabilities Assumed and the Fair Value of Consideration Business Combination [Table Text Block] Adjustments to reconcile net income to cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Due in 2029 Long-Term Debt, Maturity, Year Three Securities Sold under Agreements to Repurchase [Abstract] Securities Sold under Agreements to Repurchase [Abstract] Unrecognized Gains and Losses on Held-to-Maturity Securities Amortization of unrecognized losses on    held-to-maturity securities transferred    from available-for-sale Accumulated Unrealized Gains Losses On Held To Maturity Securities, Parent [Member] Accumulated unrealized gains losses on held-to-maturity securities. Weighted- Average Term Extension (in months) Financing Receivable, Modified, Weighted-Average Term Increase from Modification 12 months or longer Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Cash Flows From Financing Activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Financial Instruments Financial Instruments [Domain] Originated four years before current year Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year Assets Derivative Asset Intangible Asset, Finite-Lived, Class Intangible Asset, Finite-Lived, Class [Axis] GOODWILL AND OTHER INTANGIBLE ASSETS Intangible Asset and Goodwill [Text Block] Underlying Securities Award Underlying Securities Amount Estimate of Fair Value Measurement Estimate of Fair Value Measurement [Member] State Income Tax Jurisdiction, Domestic State and Local [Member] Preferred Stock Preferred Stock [Member] Operating leases Operating Lease, Weighted Average Discount Rate, Percent Investment Program, Proportional Amortization Method, Applied, Amortization Expense, Statement of Cash Flows [Extensible Enumeration] Investment Program, Proportional Amortization Method, Applied, Amortization Expense, Statement of Cash Flows [Extensible Enumeration] Modified in Period Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount Balance at beginning of period Balance at end of period Off-Balance-Sheet, Credit Loss, Liability Schedule of Components of Lease Expense Lease, Cost [Table Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Available-for-Sale, Less than 12 months, Fair Value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Current Fiscal Year End Date Current Fiscal Year End Date Deposits Net Change Interest-Bearing Deposits, Domestic One to five years Debt Securities, Available-for-Sale, Weighted Average Yield, Maturity, after Year One Through Five Investment securities held to maturity Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Provision for credit losses Provision for credit losses Provision for credit losses Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal) Derivative [Line Items] Derivative [Line Items] Net amount presented in the Consolidated Balance Sheet Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Dividends per common share (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Schedule of Expected Maturities of Investment Securities Portfolio Investments Classified by Contractual Maturity Date [Table Text Block] Proceeds from company-owned life insurance death benefits Proceeds from Life Insurance Policy Reclassification adjustment for (gains) losses realized in net income Gain (Loss) Reclassified from AOCI into Income Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Preferred dividends (in dollars per share) Preferred Stock, Dividends Per Share, Declared Measure: Measure [Axis] Bremer Bremer [Member] Bremer Finance lease term Lessee, Finance Lease, Term of Contract Nontaxable Interest Income, Securities, Operating, Tax Exempt Variable rates Long-Term Debt, Percentage Bearing Variable Interest, Percentage Rate Equity Components Equity Components [Axis] Total income taxes paid (net of refunds) Income Tax Paid, after Refund Received Valuation allowance recorded Deferred Tax Assets, Valuation Allowance Number of securities in security portfolio Number Of Securities In Security Portfolio The number of securities included in the investment securities portfolio. Entity Interactive Data Current Entity Interactive Data Current One to five years Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five Available-for-sale, Fair Value Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract] Entity Small Business Entity Small Business Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Net interest income Interest income (expense) Interest Income Interest Income (Expense), Operating MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] 2029 Finance Lease, Liability, to be Paid, Year Three Document Type Document Type Beyond ten years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 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] Allowance for credit losses for available-for-sale debt securities Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Interest rate swaps, collars, and floors on loan pools Variable Interest Rate Swaps, Collars And Floors [Member] Variable interest rate collars and floors. Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Debt Securities, Trading, and Equity Securities, FV-NI [Table] Debt Securities, Trading, and Equity Securities, FV-NI [Table] Local Phone Number Local Phone Number Mortgage contracts Mortgage Contract [Member] Mortgage Contract [Member] Five to ten years Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity, after Year 5 Through 10 Held-to-Maturity, Weighted Average Yield Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity [Abstract] Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Derivative collateralize position amount Derivative Instruments, Collateralized Position Amount Derivative Instruments, Collateralized Position Amount Average amount outstanding during the period Short-Term Debt, Average Outstanding Amount Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Axis] 2030 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Four New Accounting Pronouncements or Change in Accounting Principle [Table] Accounting Standards Update and Change in Accounting Principle [Table] Executive Category: Executive Category [Axis] Available-for-Sale Debt Securities, Available-for-Sale, Amortized Cost [Abstract] Unobservable Input Loan, Held-for-Sale, Measurement Input Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Direct Direct Portfolio Segment [Member] Direct Portfolio Segment Supplemental Cash Flow Information: Supplemental Cash Flow Information [Abstract] PEO Name PEO Name Accrued expenses and other liabilities Accrued Liabilities and Other Liabilities Gains and Losses on Hedges Gains and losses on hedges    Interest rate contracts Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] 12 months or longer Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value Cash received from merger, net Cash Acquired from Acquisition Weighted-Average Remaining Lease Term (in Years) Lessee Weighted Average Remaining Lease Term [Abstract] Lessee, weighted-average remaining lease term. Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Cash and due from banks Cash and Due from Banks Collateral Dependent Loans Collateral Dependent Impaired Loans [Member] Collateral Dependent Impaired Loans Schedule of Past Due Financing Receivables Financing Receivable, Past Due [Table Text Block] Current Financial Asset, Not Past Due [Member] Assets Business Combination, Recognized Asset Acquired, Asset [Abstract] Investment securities held-to-maturity: Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss [Abstract] Fair Value Debt Securities, Held-to-Maturity, Unrealized Loss Position, Fair Value [Abstract] Preferred dividends Preferred dividends Preferred Stock Dividends, Income Statement Impact Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Company-owned life insurance Increase in cash surrender value of company-owned life insurance Bank Owned Life Insurance Income Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Net credit exposure Derivative Liability, Subject to Master Netting Arrangement, after Offset and Deduction Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Measurement Frequency [Domain] Measurement Frequency [Domain] Debt Instrument Debt Instrument [Axis] Share-based compensation expense Share-Based Payment Arrangement, Noncash Expense Interest Expense Interest Expense, Operating and Nonoperating [Abstract] Salaries and employee benefits Labor and Related Expense Total Lease, Cost Home equity Home Equity Portfolio Segment [Member] Home Equity Portfolio Segment Customer interest rate contracts Customer Derivative Instrument [Member] Customer derivative instrument. Proceeds from maturities, prepayments, and calls of investment securities held-to-maturity Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities Net income per common share - basic (in dollars per share) Basic Net Income Per Common Share (in dollars per share) Earnings Per Share, Basic Measurement Input Type Measurement Input Type [Axis] Insider Trading Arrangements [Line Items] Amortization of tax credit investments Amortization of tax credit investments Investment Program, Proportional Amortization Method, Elected, Equity Method Investment, Income (Loss) from Tax Credit Investment Nonaccrual Non Accrual [Member] Non accrual. Portfolio Segment After Reclassifications Segment Portfolio Reclassification, Adjusted Balance [Member] Segment Portfolio Reclassification, Adjusted Balance Investment, Equity Equity Method Investment Qualified Affordable Housing Project Investments Equity method investment qualified affordable housing project investments. Schedule of Securities Sold under Agreements to Repurchase and Weighted-Average Interest Rates Schedule of Short-Term Debt [Table Text Block] Company-owned life insurance Bank Owned Life Insurance Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Company-owned life insurance Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Company-Owned Life Insurance Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Company-Owned Life Insurance Other borrowings Total other borrowings Total Other Borrowings Loans held-for-sale Loans Held For Sale [Member] Residential loans held for sale. Fair Value Measurement [Domain] Fair Value Measurement [Domain] Recoveries Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Recovery Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover page. Cover [Abstract] Amortization of unrecognized losses on securities transferred     from available-for-sale OCI, Debt Securities, Available-for-Sale, Transfer to Held-to-Maturity, Adjustment from AOCI for Amortization of Gain (Loss), before Tax Weighted-average interest rate at end of year Short-Term Debt, Weighted Average Interest Rate, at Point in Time One year before current fiscal year Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff Equity Awards Adjustments Equity Awards Adjustments [Member] Hedging Relationship Hedging Relationship [Domain] Net deferred tax assets Deferred Tax Assets, Net Schedule of Supplemental Cash Flow Information Related to Leases Schedule Of Supplemental Cash Flow Information Related To Leases [Table Text Block] Schedule of supplemental cash flow information related to leases. Securities sold under agreements to repurchase Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase1 Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase1 Increase (decrease) in accrued expenses and other liabilities Increase (Decrease) in Other Operating Liabilities Pass Pass [Member] Income Tax Authority Income Tax Jurisdiction [Domain] Other securities Other Debt Obligations [Member] Net (gains) losses on sales of loans and other assets Gain (Loss) on Disposition of Assets for Financial Service Operations Schedule of Proceeds from Sales or Calls and Realized Gain and Losses of Available-for-Sale Investment Securities and Other Securities Schedule of Realized Gain (Loss) [Table Text Block] Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Nontaxable Interest And Fee Income Nontaxable Amount of operating interest income, including amortization and accretion of premiums and discounts, on loans and leases receivable exempt from state, federal and other income tax. Number of real estate properties Number of Real Estate Properties Hedging Designation Hedging Designation [Domain] Class of Stock Class of Stock [Domain] Operating cash flows from finance leases Finance Lease, Interest Payment on Liability Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Checking and NOW Deposits, Negotiable Order of Withdrawal (NOW) Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Income Tax Authority Income Tax Jurisdiction [Axis] INCOME TAXES Income Tax Disclosure [Text Block] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Total consideration Business Combination, Consideration Transferred Tax Expense (Benefit) Recognized Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization Expense Entity Filer Category Entity Filer Category Available-for-Sale, Fair Value Debt Securities, Available-for-Sale, Unrealized Loss Position Investment securities purchased but not settled Investment Securities Purchased But Not Settled Investment securities purchased but not settled. Finance lease right-of-use assets obtained in exchange for lease obligations Right-of-Use Asset Modified And Obtained in Exchange for Finance Lease Liability Right-of-Use Asset Modified And Obtained in Exchange for Finance Lease Liability Schedule of Offsetting Liabilities Offsetting Liabilities [Table Text Block] Financing Receivable, Nonaccrual [Line Items] Financing Receivable, Nonaccrual [Line Items] Greater Than 90 days Maturity Greater than 90 Days [Member] Finance Leases Finance Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract] Due in 2027 Federal Home Loan Bank, Advance, Maturity, Year One Loan participations sold Loan Participations Sold Amount of loan participations sold to other financial institutions. 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Liabilities Derivative Liability Interest income for residential loans held for sale Interest and Fee Income, Loans, Commercial and Residential, Real Estate Entity Address, Address Line One Entity Address, Address Line One Operating lease right-of-use assets obtained in exchange for lease obligations Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Income tax expense Income tax (expense) benefit Income tax expense Income Tax Expense (Benefit) Fair value hedges: Fair Value Hedging [Member] Total Held To Maturity Securities Debt Maturities Weighted Average Yield Weighted average yield on total held-to-maturity securities. Charge-offs Total Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff Loans, net: Accrued Interest, after Allowance for Credit Loss [Abstract] RECENT ACCOUNTING PRONOUNCEMENTS Accounting Standards Update and Change in Accounting Principle [Text Block] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Unamortized debt issuance costs related to subordinated debentures Unamortized Debt Issuance Expense Loan Restructuring Modification [Domain] Loan Restructuring Modification [Domain] Discounted cash flow Valuation Technique, Discounted Cash Flow [Member] Statement [Table] Statement [Table] Income Taxes [Line Items] Income Taxes [Line Items] Income taxes. Originated one year before current year Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year Schedule of Nonaccrual and Past Due Loans Financing Receivable, Nonaccrual [Table Text Block] Gross amounts recognized Derivative assets Derivative Asset, Subject to Master Netting Arrangement, before Offset Fair Value Loan, Held-for-Sale, Fair Value Disclosure BASIS OF PRESENTATION Basis of Presentation and Significant Accounting Policies [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract]