Banking and Thrift [Abstract] Regulatory Capital Regulatory Capital Requirements under Banking Regulations [Text Block] Repossessed Assets [Abstract] Other Real Estate Owned Roll Forward Real Estate Acquired Through Foreclosure, Roll Forward [Table Text Block] Real Estate Acquired Through Foreclosure, Roll Forward [Table Text Block] Business Combinations [Abstract] Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table] Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Mountain West Bank Mountain West Bank [Member] Mountain West Bank [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Core Deposits [Member] Core Deposits [Member] Acquired Finite-Lived Intangible Assets [Line Items] Acquired Finite-Lived Intangible Assets [Line Items] Finite-lived Intangible Assets Acquired Finite-lived Intangible Assets Acquired Finite-Lived Intangible Asset, Useful Life Finite-Lived Intangible Asset, Useful Life Receivables [Abstract] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Schedule of Financing Receivable, Allowance for Credit Losses [Table] Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] Real Estate Real Estate Portfolio Segment [Member] Real Estate Portfolio Segment [Member] Consumer Consumer Portfolio Segment [Member] Commercial Commercial Portfolio Segment [Member] Agriculture Agriculture Portfolio Segment [Member] Agriculture Portfolio Segment [Member] Other Other Portfolio Segment [Member] Other Portfolio Segment [Member] Financing Receivable, Allowance for Credit Losses [Line Items] Financing Receivable, Allowance for Credit Losses [Line Items] Allowance for Loan and Lease Losses [Roll Forward] Allowance for Loan and Lease Losses [Roll Forward] Beginning balance Loans and Leases Receivable, Allowance Provision charged to operating expense Provision for Loan and Lease Losses Less loans charged-off Allowance for Loan and Lease Losses, Write-offs Add back recoveries of loans previously charged-off Allowance for Loan and Lease Loss, Recovery of Bad Debts Ending balance Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract] Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract] Allowance for loan losses: Loans and Leases Receivable, Allowance [Abstract] Loans individually evaluated for impairment Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment Loans collectively evaluated for impairment Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment Ending balance Total loans: Loans and Leases Receivable Disclosure [Abstract] Individually evaluated for impairment Financing Receivable, Individually Evaluated for Impairment Individually evaluated for impairment Financing Receivable, Collectively Evaluated for Impairment Total loans Loans and Leases Receivable, Gross Subordinated Debentures Held by Subsidiary Trusts [Abstract] Subordinated Debentures Held by Subsidiary Trusts [Abstract] Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Estimated Fair Value Estimate of Fair Value Measurement [Member] Carrying Amount Reported Value Measurement [Member] Debt Security [Axis] Debt Security [Axis] Major Types of Debt Securities [Domain] Major Types of Debt Securities [Domain] Obligations of U.S. government agencies US Government Agencies Debt Securities [Member] U.S. agency residential mortgage-backed securities & collateralized mortgage obligations Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Private mortgage-backed securities Mortgage-backed Securities, Issued by Private Enterprises [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Change During Period Changes Measurement [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value Measured on a Recurring Basis Fair Value, Measurements, Recurring [Member] Fair Value Measured on a Non-recurring Basis Fair Value, Measurements, Nonrecurring [Member] Other Real Estate Owned Expense, Type [Axis] Other Real Estate Owned Expense, Type [Axis] Other Real Estate Owned Expense, Type [Axis] Other Real Estate Owned Expense, Type [Domain] Other Real Estate Owned Expense, Type [Domain] Other Real Estate Owned Expense, Type [Domain] 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] Investment securities available-for-sale Available-for-sale Securities Mortgage servicing rights Servicing Asset at Fair Value, Amount Impaired loans Loans Receivable, Impaired, Fair Value Disclosure Loans Receivable, Impaired, Fair Value Disclosure Other real estate owned Real Estate Acquired Through Foreclosure, Fair Value Disclosure Real Estate Acquired Through Foreclosure, Fair Value Disclosure Real Estate Acquired Through Foreclosure, Valuation Adjustments Real Estate Acquired Through Foreclosure, Valuation Adjustments Real Estate Acquired Through Foreclosure, Valuation Adjustments Impairment of real estate, received updated appraisal Impairment of real estate, received updated appraisal Impairment of real estate, received updated appraisal Long-lived assets to be disposed of by sale Assets Held-for-sale, Long Lived, Fair Value Disclosure Related Allowance Impaired Financing Receivable, Related Allowance Impaired Financing Receivable, Related Allowance, Partial Loan Charge-Offs Impaired Financing Receivable, Related Allowance, Partial Loan Charge-Offs Impaired Financing Receivable, Related Allowance, Partial Loan Charge-Offs Impairment of Real Estate, Change in Management Estimates Impairment of Real Estate, Change in Management Estimates Impairment of Real Estate, Change in Management Estimates Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Schedule of Recognized Identifiable Assets Acquired and LIabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Table Text Block] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Class A Common Stock Common Class A [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Business Acquisition [Line Items] Business Acquisition [Line Items] Number of Subsidiary Banks Number of Subsidiary Banks Number of Subsidiary Banks Number of Shared Markets Number of Shared Markets Number of Shared Markets Business Acquisition, Effective Date of Acquisition Business Acquisition, Effective Date of Acquisition Business Acquisition Conversion Share Rate Business Acquisition Conversion Share Rate Business Acquisition Conversion Share Rate Business Acquisition Conversion Rate Business Acquisition Conversion Rate Business Acquisition Conversion Rate Payments to Acquire Businesses, Gross Payments to Acquire Businesses, Gross Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Business Combination, Consideration Transferred Business Combination, Consideration Transferred Business Acquisition, Share Price Business Acquisition, Share Price Business Combination, Acquisition Related Costs Business Combination, Acquisition Related Costs Equity [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Class B Common Stock Common Class B [Member] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Board of Directors Board of Directors [Member] Board of Directors [Member] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Share Repurchase Program November 2013 Board Approved Stock Repurchase Program [Member] November 2013 Board Approved Stock Repurchase Program [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2006 Equity Compensation Plan 2006 Equity Compensation Plan [Member] 2006 Equity Compensation Plan [Member] Class of Stock [Line Items] Class of Stock [Line Items] Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding Business Acquisition, Equity Interest Issued or Issuable, Value Assigned Business Acquisition, Equity Interest Issued or Issuable, Value Assigned Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Share-based Compensation Arrangement by Share-based Payment Award, Aggregate Value of Shares Issued Share-based Compensation Arrangement by Share-based Payment Award, Aggregate Value of Shares Issued Share-based Compensation Arrangement by Share-based Payment Award, Aggregate Value of Shares Issued Stock Repurchased and Retired During Period, Shares Stock Repurchased and Retired During Period, Shares Payments for Repurchase of Common Stock Payments for Repurchase of Common Stock Stock Repurchase Program, Remaining Authorized Repurchase Amount Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Financial assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Investment securities held-to-maturity Held-to-maturity Securities, Fair Value Accrued interest receivable Accrued Interest Receivable, Fair Value Disclosure Accrued Interest Receivable, Fair Value Disclosure Net loans Loans Receivable, Fair Value Disclosure Total financial assets Assets, Fair Value Disclosure Financial liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Total deposits, excluding time deposits Deposits, Excluding Time Deposits, Fair Value Disclosure Deposits, Excluding Time Deposits, Fair Value Disclosure Time deposits Time Deposits, Fair Value Disclosure Time Deposits, Fair Value Disclosure Securities sold under repurchase agreements Financial Instruments Sold, Not yet Purchased, at Fair Value Other borrowed funds Other Borrowed Funds, Fair Value Disclosure Other Borrowed Funds, Fair Value Disclosure Accrued interest payable Accrued Interest Payable, Fair Value Disclosure Accrued Interest Payable, Fair Value Disclosure Long-term debt Other Long Term Debt, Fair Value Disclosure Other Long Term Debt, Fair Value Disclosure Subordinated debentures held by subsidiary trusts Subordinated Debt Obligations, Fair Value Disclosure Total financial liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Statement, Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common stock Common Stock Including Additional Paid in Capital [Member] Retained earnings Retained Earnings [Member] Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss) [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance Stockholders' Equity Attributable to Parent Comprehensive income: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Net income Net Income (Loss) Attributable to Parent Other comprehensive income, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Common stock transactions: Common Stock Transactions [Abstract] Common Stock Transactions. Common shares purchased and retired 387,967 and 25,677 in 2014 and 2013, respectively Stock Repurchased and Retired During Period, Value Common shares issued 1,402,811 in 2014 and 26,096 in 2013 Stock Issued During Period, Value, New Issues Non-vested common shares issued 147,876 and 120,873 in 2014 and 2013 respectively Stock Issued During Period, Value, Restricted Stock Award, Gross 17,741 and 10,517 non-vested common shares forfeited in 2014 and 2013 respectively Stock Issued During Period, Value, Restricted Stock Award, Forfeitures 372,880 and 688,864 stock options exercised, net of 166,780 and 336,442 shares tendered in payment of option price and income tax withholding amounts in 2014 and 2013 respectively Stock Issued During Period, Value, Stock Options Exercised Tax benefit of stock-based compensation Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Stock-based compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Cash dividends declared: Dividends [Abstract] Common ($0.48 per share) in 2014 and ($0.27 per share) in 2013 Dividends, Common Stock, Cash Ending Balance Change in net unrealized Gain during period: Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Reclassification Adjustments, Net of Tax [Abstract] Change in net unrealized gain during period, before tax amount Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Change in net unrealized gain during period, tax expense (benefit) Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Change in net unrealized gain during period, net of tax amount Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Reclassification adjustment for gains included in net income: Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract] Reclassification adjustment for gains included in net income, before tax amount Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Reclassification adjustment for gains included in net income, tax expense (benefit) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Reclassification adjustment for gains included in net income, net of tax amount Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Change in net actuarial loss: Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract] Change in net actuarial loss, before tax amount Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Tax Change in net actuarial loss, tax expense (benefit) Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Tax Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Tax Change in net actuarial loss, net of tax amount Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Other comprehensive income (loss), before tax Other Comprehensive Income (Loss), before Tax Total other comprehensive income, tax expense (benefit) Other Comprehensive Income (Loss), Tax Total other comprehensive income, net of tax amount Other Comprehensive Income (Loss), Net of Tax Investments, Debt and Equity Securities [Abstract] Schedule of Available for Sale and Held-to-Maturity Securities [Table] Schedule of Available for Sale and Held-to-Maturity Securities [Table] Schedule of Available for Sale and Held-to-Maturity Securities [Table] Investment Securities, Description [Axis] Investment Securities, Description [Axis] Investment Securities, Description [Axis] Investment Securities, Description [Domain] Investment Securities, Description [Domain] Investment Securities, Description [Domain] Callable Within One Year Callable Within One Year [Member] Callable Within One Year [Member] Callable Structured Notes Callable Structured Notes [Member] Callable Structured Notes [Member] Schedule of Available for Sale and Held-to-Maturity Securities [Line Items] Schedule of Available for Sale and Held-to-Maturity Securities [Line Items] Schedule of Available for Sale and Held-to-Maturity Securities [Line Items] Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract] Available-for-Sale Amortized Cost, Within One Year Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost Basis Available-for-Sale Amortized Cost, After One Year but Within Five Years Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis Available-for-Sale Amortized Cost, After Five Years but Within Ten Years Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost Basis Available-for-Sale Amortized Cost, After Ten Years Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Amortized Cost Basis Available-for-Sale, Amortized Cost Available-for-sale Debt Securities, Amortized Cost Basis Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] Available-for-Sale Estimated Fair Value, Within One Year Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value Available-for-Sale Estimated Fair Value, After One Year but Within Five Years Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value Available-for-Sale Estimated Fair Value, After Ten Years Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Fair Value Available-for-Sale Estimated Fair Value, After Five Years but Within Ten Years Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Fair Value Available-for-Sale, Estimated Fair Value Available-for-sale Securities, Debt Securities Held-to-maturity Securities, Debt Maturities, Net Carrying Amount Held-to-maturity Securities, Debt Maturities, Net Carrying Amount [Abstract] Held-to-Maturity Amortized Cost, Within One Year Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount Held-to-Maturity Amortized Cost, After One Year but Within Five Years Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount Held-to-Maturity Amortized Cost, After Five Years but Within Ten Years Held-to-maturity Securities, Debt Maturities, after Five Through Ten Years, Net Carrying Amount Held-to-Maturity Amortized Cost, After Ten Years Held-to-maturity Securities, Debt Maturities, after Ten Years, Net Carrying Amount Held-to-Maturity, Amortized Cost Held-to-maturity Securities Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract] Held-to-Maturity Estimated Fair Value, Within One Year Held-to-maturity Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value Held-to-Maturity Estimated Fair Value, After One Year but Within Five Years Held-to-maturity Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value Held-to-Maturity Estimated Fair Value, After Five Years but Within Ten Years Held-to-maturity Securities, Debt Maturities, Rolling Year Six Through Ten, Fair Value Held-to-Maturity Estimated Fair Value, After Ten Years Held-to-maturity Securities, Debt Maturities, Rolling after Ten Years, Fair Value Held-to-Maturity, Estimated Fair Value Available-for-sale Securities and Held-to-maturity Securities Available-for-sale Securities and Held-to-maturity Securities [Abstract] Investment Securities Primarily Classified as Available-for-Sale, Amortized Costs, After One Year but Within Five Years Investment Securities, Primarily Classified as Available-for-Sale, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis Investment Securities, Primarily Classified as Available-for-Sale, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis Investment Securities Primarily Classified as Available-for-Sale, Fair Value, After One Year but Within Five Years Investment Securities, Primarily Classified as Available-for-Sale, Debt Maturities, Rolling Year Two Through Five, Fair Value Investment Securities, Primarily Classified as Available-for-Sale, Debt Maturities, Rolling Year Two Through Five, Fair Value Earnings Per Share [Abstract] Schedule of Earnings Per Share, Basic and Diluted [Table] Schedule of Earnings Per Share, Basic and Diluted [Table] Schedule of Earnings Per Share, Basic and Diluted [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock Options Employee Stock Option [Member] Unvested Restricted Stock Restricted Stock [Member] Earnings Per Share, Basic and Diluted [Line Items] Earnings Per Share, Basic and Diluted [Line Items] Earnings Per Share, Basic and Diluted [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Net Income (Loss) Available to Common Stockholders, Basic Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Net income Weighted Average Number of Shares Outstanding, Basic and Diluted Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract] Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract] Weighted average common shares outstanding for basic earnings per share computation Weighted Average Number of Shares Outstanding, Basic Dilutive effect of stock-based compensation Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted average common shares outstanding for diluted earnings per common share computation Weighted Average Number of Shares Outstanding, Diluted Earnings Per Share, Basic and Diluted Earnings Per Share, Basic and Diluted [Abstract] Basic earnings per common share Earnings Per Share, Basic Diluted earnings per common share Earnings Per Share, Diluted Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Director [Member] Director [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Stock Repurchased and Retired During Period, Weighted Average Price Stock Repurchased and Retired During Period, Weighted Average Price Stock Repurchased and Retired During Period, Weighted Average Price Gross realized gains Available-for-sale Securities, Gross Realized Gains Gross realized losses Available-for-sale Securities, Gross Realized Losses New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Recent Authoritative Accounting Guidance New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Allowance For Loan Losses Allowance for Credit Losses [Text Block] Mountain West Financial Corp Acquisition, As Recorded by MWFC Mountain West Financial Corp Acquisition, As Recorded by MWFC [Member] Mountain West Bank Acquisition, As Recorded by MWFC [Member] Mountain West Financial Corp Acquisition, Fair Value Adjustment Mountain West Bank Acquisition, Fair Value Adjustment [Member] Mountain West Financial Corp Acquisition, Fair Value Adjustment [Member] Mountain West Financial Corp Acquisition, As Recorded by the Company Mountain West Bank Acquisition, As Recorded by the Company [Member] Mountain West Financial Corp Acquisition, As Recorded by Company [Member] Cash and Cash Equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Investment Securities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Marketable Securities Loans Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans and Leases Receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans and Leases Receivable Allowance for Loan Losses Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans and Leases Receivable, Allowance Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans and Leases Receivable, Allowance Premises and Equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment 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 Deferred Tax Assets, Net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets, Net of Valuation Allowance Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets, Net of Valuation Allowance Core Deposit Intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Other Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Assets Total Assets Acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Deposits Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deposits Other Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Liabilities Subordinated Debentures Held by Subsidiary Trusts Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Subordinated Debentures Held by Subsidiary Trusts Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Subordinated Debentures Held by Subsidiary Trusts Total Liabilities Assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Net Assets Acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Goodwill Goodwill Other Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Computation of Basic and Diluted Earnings per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Allowance for Loan Losses by Portfolio Segment Allowance for Credit Losses on Financing Receivables [Table Text Block] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period [Abstract] Contractually Required Principal and Interest Payments Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Contractually Required Payments Receivable at Acquisition Contractual Cash Flows Not Expected to be Collected Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Non-Accretable Yield Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Contractual Cash Flows Not Expected to be Collected Cash Flows Expected to be Collected Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Cash Flows Expected to be Collected at Acquisition Interest Component of Cash Flows Expected to be Collected Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Internet Component Expected to be Collected Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Internet Component Expected to be Collected Fair Value of Acquired Credit-Impaired Loans Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, at Acquisition, at Fair Value Income Statement [Abstract] Statement, Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Interest income: Interest Income (Expense), Net [Abstract] Interest and fees on loans Interest and Fee Income, Loans and Leases Interest and dividends on investment securities: Interest and Dividend Income, Operating [Abstract] Taxable Interest Income, Securities, Operating, Taxable Exempt from federal taxes Interest Income, Securities, Operating, Tax Exempt Interest on deposits in banks Interest Income, Domestic Deposits Interest on federal funds sold Interest Income, Federal Funds Sold Total interest income Interest and Dividend Income, Operating Interest expense: Interest Expense [Abstract] Interest on deposits Interest Expense, Deposits Interest on securities sold under repurchase agreements Interest Expense, Securities Sold under Agreements to Repurchase Interest on other borrowed funds Interest Expense, Short-term Borrowings Interest on long-term debt Interest Expense, Other Long-term Debt Interest on preferred stock pending redemption Interest Expense, Preferred Stock Pending Redemption Interest Expense, Preferred Stock Pending Redemption Interest on subordinated debentures held by subsidiary trusts Interest Expense, Junior Subordinated Debentures Total interest expense Interest Expense Net interest income Interest Income (Expense), Net Provision for loan losses Net interest income after provision for loan losses Interest Income (Expense), after Provision for Loan Loss Non-interest income: Noninterest Income [Abstract] Other service charges, commissions and fees Fees and Commissions, Other Income from the origination and sale of loans Income From Origination And Sale Of Loans Income from origination and sale of loans. Investment Advisory, Management and Administrative Fees Investment Advisory, Management and Administrative Fees Service charges on deposit accounts Fees and Commissions, Depositor Accounts Investment securities gains, net Gain (Loss) on Sale of Debt Investments Other income Noninterest Income, Other Operating Income Total non-interest income Noninterest Income Non-interest expense: Noninterest Expense [Abstract] Salaries and wages Labor and Related Expense Employee benefits Other Labor-related Expenses Occupancy, net Occupancy, Net Furniture and equipment Equipment Expense Outsourced technology services Outsourced Technology Services Outsourced technology services. OREO expense, net of income Other Real Estate Owned Expense Net Of Income Other Real Estate Owned expense net of income. Professional fees Professional Fees FDIC insurance premiums Federal Deposit Insurance Corporation Premium Expense Mortgage servicing rights amortization Amortization of Mortgage Servicing Rights (MSRs) Mortgage servicing rights impairment recovery Mortgage Servicing Rights (MSR) Impairment (Recovery) Core deposit intangibles amortization Amortization of Intangible Assets Other expenses Other Noninterest Expense Non-core acquisition expenses Total non-interest expense Noninterest Expense Income before income tax expense Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Basic earnings per common share Diluted earnings per common share Schedule of Comprehensive Income (Loss) Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Commercial real estate Commercial Real Estate Other Receivable [Member] Land acquisition & development construction real estate Land Acquisition & Development Construction Financing Receivable [Member] Land Acquisition & Development Construction Financing Receivable [Member] Residential construction real estate Residential Real Estate Construction Financing Receivable [Member] Residential Real Estate Construction Financing Receivable [Member] Commercial construction real estate Commercial Real Estate Construction Financing Receivable [Member] Total construction loans Real Estate Construction Financing Receivable [Member] Real Estate Construction Financing Receivable [Member] Residential real estate Residential Mortgage [Member] Agricultural real estate Agricultural Real Estate Financing Receivable [Member] Agricultural Real Estate Financing Receivable [Member] Total real estate loans Real Estate Financing Receivable [Member] Real Estate Financing Receivable [Member] Commercial Commercial Financing Receivable [Member] Commercial Financing Receivable [Member] Agricultural Agricultural Financing Receivable [Member] Agricultural Financing Receivable [Member] Loans and Leases Receivable Recorded Investment, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Impaired Financing Receivable, Unpaid Principal Balance Impaired Financing Receivable, Unpaid Principal Balance [Abstract] Unpaid Total Principal Balance Impaired Financing Receivable, Unpaid Principal Balance Recorded Investment With No Allowance Impaired Financing Receivable, with No Related Allowance, Recorded Investment Recorded Investment With Allowance Impaired Financing Receivable, with Related Allowance, Recorded Investment Total Recorded Investment Impaired Financing Receivable, Recorded Investment Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income [Abstract] Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income [Abstract] Average Recorded Investment Impaired Financing Receivable, Average Recorded Investment Income Recognized Impaired Financing Receivable, Interest Income, Accrual Method and Cash Basis Method Impaired Financing Receivable, Interest Income, Accrual Method and Cash Basis Method Interest Income on Impaired Loans If Interest Had Been Accrued Impaired Financing Receivable, Interest Income, Accrual Method Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Dividends Payable, Amount Per Share Dividends Payable, Amount Per Share Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Provision for loan losses Provision for Loan Losses Expensed Net (gain) loss on disposal of property and equipment Gain (Loss) on Disposition of Property Plant Equipment Depreciation and amortization Depreciation, Depletion and Amortization Net premium amortization on investment securities Accretion (Amortization) of Discounts and Premiums, Investments Net gains on investment securities transactions Net gains on sales of mortgage loans held for sale Gain (Loss) on Sale of Loans and Leases Net gain on sale of OREO Gains (Losses) on Sales of Other Real Estate OREO valuation adjustments Asset Impairment Charges Net impairment (reversal of impairment) of mortgage servicing rights Deferred income tax expense Deferred Income Tax Expense (Benefit) Net increase in cash surrender value of company-owned life insurance policies Life Insurance, Corporate or Bank Owned, Change in Value Stock-based compensation expense Share-based Compensation Tax benefits from stock-based compensation expense Deferred Tax Expense from Stock Options Exercised Excess tax benefits from stock-based compensation Excess Tax Benefit from Share-based Compensation, Operating Activities Originations of loans held for sale Payments for Origination of Mortgage Loans Held-for-sale Proceeds from sales of loans held for sale Proceeds from Sale of Mortgage Loans Held-for-sale Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Increase in interest receivable Increase (Decrease) in Accrued Interest Receivable, Net Decrease in other assets Increase (Decrease) in Other Operating Assets Decrease in accrued interest payable Increase (Decrease) in Interest Payable, Net Decrease in accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of held-to-maturity investment securities Payments to Acquire Held-to-maturity Securities Purchases of available-for-sale investment securities Payments to Acquire Available-for-sale Securities Proceeds from maturities and paydowns of held-to-maturity investment securities Proceeds from Sale and Maturity of Held-to-maturity Securities Proceeds from maturities and paydowns of available-for-sale investment securities Proceeds from Sale and Maturity of Available-for-sale Securities Purchases of company-owned life insurance Payments to Acquire Life Insurance Policies Proceeds from sales of mortgage servicing rights Payments for (Proceeds from) Mortgage Servicing Rights Extensions of credit to customers, net of repayments Payments for (Proceeds from) Other Loans and Leases Recoveries of loans charged-off Proceeds from Recoveries of Loans Previously Charged off Proceeds from sales of OREO Proceeds from Sale of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans Acquisition of bank and bank holding company, net of cash and cash equivalents received Payments to Acquire Businesses, Net of Cash Acquired Capital expenditures, net of sales Payments for (Proceeds from) Productive Assets Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Net increase (decrease) in deposits Increase (Decrease) in Deposits Net decrease in repurchase agreements Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase Net increase (decrease) in short-term borrowings Proceeds from (Repayments of) Short-term Debt Repayments of long-term debt Repayments of Other Long-term Debt Redemption of preferred stock Payments for Repurchase of Preferred Stock and Preference Stock Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Excess tax benefits from stock-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Purchase and retirement of common stock Dividends paid to common stockholders Payments of Ordinary Dividends, Common Stock Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of period Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid during the period for income taxes Income Taxes Paid Cash paid during the period for interest expense Interest Paid Business Acquisition, Pro Forma Information [Abstract] Nonrecurring Adjustment [Axis] Nonrecurring Adjustment [Axis] Nonrecurring Adjustment [Domain] Nonrecurring Adjustment [Domain] Business Acquisition, Pro Forma Revenue Business Acquisition, Pro Forma Revenue Business Acquisition, Pro Forma Income Business Acquisition, Pro Forma Income (Loss) from Continuing Operations before Changes in Accounting and Extraordinary Items, Net of Tax Expenses Related to Acquisition Excluded from Pro Forma Net Income Expenses Related to Acquisition Excluded From Pro Forma Net Income Expenses Related to Acquisition Excluded From Pro Forma Net Income Schedule of Financing Receivables Past Due [Table] Schedule of Financing Receivables Past Due [Table] Indirect consumer Consumer Indirect Financing Receivable [Member] Consumer Indirect Financing Receivable [Member] Other consumer Consumer Other Financing Receivable [Member] Credit card consumer Consumer Credit Card Financing Receivable [Member] Total consumer loans Consumer Financing Receivable [Member] Consumer Financing Receivable [Member] Other, including overdrafts Other Financing Receivable, Including Overdrafts [Member] Other Financing Receivable, Including Overdrafts [Member] Loans held for investment Loans and Leases Held for Investment [Member] Loans and Leases Held for Investment [Member] Mortgage loans originated for sale Mortgage Loans Held for Sale [Member] Mortgage Loans Held for Sale [Member] Total loans Loans and Leases Receivable [Member] Loans and Leases Receivable [Member] Loans and Leases Receivable Recorded Investment, Past Due [Line Items] Financing Receivable, Recorded Investment, Past Due [Line Items] 30 to 59 Days Past Due Financing Receivable, Recorded Investment, 30 to 59 Days Past Due 60 to 89 Days Past Due Financing Receivable, Recorded Investment, 60 to 89 Days Past Due Greater than 90 Days Past Due Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due Total Loans 30 or More Days Past Due Financing Receivable, Recorded Investment, Past Due Current Loans Financing Receivable, Recorded Investment, Current Non-accrual Loans Financing Receivable, Recorded Investment, Nonaccrual Status Mortgage loans held for sale Disposal Group, Including Discontinued Operation, Mortgage Loans Loans held for investment Loans And Leases Receivable Held For Investment Gross carrying amount of all categories of loans and leases held in the portfolio, excluding loans held for sale. Total loans Interest Income on Non-Accrual Loans if Accrued Financing Receivable, Recorded Investment, Nonaccrual Status, Interest Income if Accrued Financing Receivable, Recorded Investment, Nonaccrual Status, Interest Income if Accrued Deteriorated Loans Transferred in [Abstract] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities [Abstract] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net, Accrual Status Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net, Accrual Status Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net, Accrual Status Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net, Non Accrual Status Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net, Non Accrual Status Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net, Non Accrual Status Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net Loans Financing Receivables [Text Block] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] State, county and municipal securities US States and Political Subdivisions Debt Securities [Member] Corporate securities Corporate Debt Securities [Member] Available-for-Sale Securities, Gross Realized Gains Available-for-sale Securities, Gross Realized Losses Available-for-Sale: Available-for-sale Securities [Abstract] Available-for-sale Securities, Gross Unrealized Gain1 Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax Available-for-sale Securities, Gross Unrealized Loss1 Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax Available-for-Sale, Estimated Fair Value Held-to-Maturity: Held-to-maturity Securities, Unclassified [Abstract] Held-to-maturity Securities, Gross Unrealized Gain1 Held-to-maturity Securities, Accumulated Unrecognized Holding Gain Held-to-maturity Securities, Gross Unrealized Loss1 Held-to-maturity Securities, Accumulated Unrecognized Holding Loss Held-to-Maturity, Estimated Fair Value Supplemental Disclosures to Consolidated Statement of Cash Flows Cash Flow, Supplemental Disclosures [Text Block] Amortized Cost and Approximate Fair Values of Investment Securities Marketable Securities [Table Text Block] Realized Gains (Losses) on Investments Realized Gain (Loss) on Investments [Table Text Block] Gross Unrealized Losses and Fair Values of Investment Securities Schedule of Unrealized Loss on Investments [Table Text Block] Maturities of Investment Securities Investments Classified by Contractual Maturity Date [Table Text Block] Subordinated Borrowings Disclosure [Text Block] Subordinated Borrowings Disclosure [Text Block] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Financing Receivable, Troubled Debt Restructuring, Concession Type [Axis] Financing Receivable, Troubled Debt Restructuring, Concession Type [Axis] Financing Receivable, Troubled Debt Restructuring, Concession Type [Axis] Financing Receivable, Troubled Debt Restructuring, Concession Type [Domain] Financing Receivable, Troubled Debt Restructuring, Concession Type [Domain] Financing Receivable, Troubled Debt Restructuring, Concession Type [Domain] Interest only period Interest Only Period Concession [Member] Interest Only Period Concession [Member] Extension of terms or maturity Extension of Terms or Maturity Concession [Member] Extension of Terms or Maturity Concession [Member] Interest rate adjustment Interest Rate Adjustment Concession [Member] Interest Rate Adjustment Concession [Member] Other Other Concession [Member] Other Concession [Member] Loans and Leases Receivable, Troubled Debt Restructuring [Line Items] Financing Receivable, Modifications [Line Items] Loans Renegotiated in Troubled Debt Restructurings Financing Receivable, Modifications, Recorded Investment Loans Renegotiated in Troubled Debt Restructurings, Non-Accrual Loans Financing Receivable, Modifications, Recorded Investment, Cash Basis Method Financing Receivable, Modifications, Recorded Investment, Cash Basis Method Loans Renegotiated in Troubled Debt Restructurings, Accrual Loans Financing Receivable, Modifications, Recorded Investment, Accrual Method Financing Receivable, Modifications, Recorded Investment, Accrual Method Number of Notes Financing Receivable, Modifications, Number of Contracts Financing Receivable, Modifications, Pre-Modification Recorded Investment Financing Receivable, Modifications, Pre-Modification Recorded Investment Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down Financing Receivable, Modifications, Subsequent Default, Number of Contracts Financing Receivable, Modifications, Subsequent Default, Number of Contracts Financing Receivable, Modifications, Subsequent Default, Recorded Investment Financing Receivable, Modifications, Subsequent Default, Recorded Investment Loans and Leases Receivable, Impaired, Commitment to Lend Loans and Leases Receivable, Impaired, Commitment to Lend Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Available-for-Sale Securities Transferred to Held-to-Maturity, Amortized Costs Available-for-Sale Securities Transferred to Held-to-Maturity, Amortized Costs Available-for-Sale Securities Transferred to Held-to-Maturity, Amortized Costs Available-for-Sale Securities Transferred to Held-to-Maturity, Fair Values Available-for-Sale Securities Transferred to Held-to-Maturity, Fair Values Available-for-Sale Securities Transferred to Held-to-Maturity, Fair Values Available-for-Sale Securities Transferred to Held-to-Maturity, Unrealized Net Gain (Loss) Available-for-Sale Securities Transferred to Held-to-Maturity, Unrealized Net Gain (Loss) Available-for-Sale Securities Transferred to Held-to-Maturity, Unrealized Net Gain (Loss) Remaining Expected Lives of Available-for-Sale Securities Transferred to Held-to-Maturity Remaining Expected Lives of Available-for-Sale Securities Transferred to Held-to-Maturity Remaining Expected Lives of Available-for-Sale Securities Transferred to Held-to-Maturity Organization, Consolidation and Presentation of Financial Statements [Abstract] Basis of Presentation Business Description and Basis of Presentation [Text Block] Subordinated Borrowings [Abstract] Schedule of Financial Instruments Subject to Mandatory Redemption [Table] Schedule of Financial Instruments Subject to Mandatory Redemption [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Trusts [Member] Trusts [Member] Trusts [Member] Schedule of Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Axis] Schedule of Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Axis] Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] Financial Instruments Subject to Mandatory Redemption, Financial Instrument [Domain] Trust Preferred Securities Subject to Mandatory Redemption [Member] Trust Preferred Securities Subject to Mandatory Redemption [Member] Common Stock Subject to Mandatory Redemption [Member] Common Stock Subject to Mandatory Redemption [Member] Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items] Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items] Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount Financial Instruments Subject to Mandatory Redemption, Settlement Terms, Share Value, Amount Schedule of Loans by Class Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Deteriorated Loans Transferred In Deteriorated Loans Transferred in, Policy [Policy Text Block] Schedule of Recorded Investment in Past Due Loans by Class Past Due Financing Receivables [Table Text Block] Schedule of Recorded Investment in Impaired Loans Impaired Financing Receivables [Table Text Block] Schedule of Loans Renegotiated in Troubled Debt Restructurings Troubled Debt Restructurings on Financing Receivables [Table Text Block] Schedule of Recorded Investment in Criticized Loans by Class and Credit Quality Indicator Financing Receivable Credit Quality Indicators [Table Text Block] Schedule of Financing Receivable, Recorded Investment, Credit Quality Indicator [Table] Schedule of Financing Receivable, Recorded Investment, Credit Quality Indicator [Table] Credit Quality Indicator [Axis] Internal Credit Assessment [Axis] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Other Assets Especially Mentioned Special Mention [Member] Substandard Substandard [Member] Doubtful Doubtful [Member] Total Criticized Loans Total Criticized Loans [Member] Total Criticized Loans [Member] Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items] Financing Receivable, Recorded Investment [Line Items] Loans held for investment Acquisitions Mergers, Acquisitions and Dispositions Disclosures [Text Block] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncement, Early Adoption [Axis] New Accounting Pronouncement, Early Adoption [Axis] New Accounting Principles, Early Adoption [Domain] New Accounting Principles, Early Adoption [Domain] Accounting Standards Update 2014-01 [Member] Accounting Standards Update 2014-01 [Member] Accounting Standards Update 2014-01 [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Investment in Affordable Housing Projects [Member] Investment in Affordable Housing Projects [Member] Investment in Affordable Housing Projects [Member] Other Commitments [Axis] Other Commitments [Axis] Other Commitments [Domain] Other Commitments [Domain] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Number of Investments in Other Assets, Noncurrent Number of Investments in Other Assets, Noncurrent Number of Investments in Other Assets, Noncurrent Other Assets Other Assets, Miscellaneous Current Income Tax Expense (Benefit) Current Income Tax Expense (Benefit) Other Commitment, Due in Next Twelve Months Other Commitment, Due in Next Twelve Months Other Commitment, Due in Second Year Other Commitment, Due in Second Year Other Commitment, Due in Third Year Other Commitment, Due in Third Year Other Commitment, Due in Fourth Year Other Commitment, Due in Fourth Year Other Commitment, Due in Fifth Year Other Commitment, Due in Fifth Year Other Commitment, Due Sixth Year Other Commitment, Due Sixth Year Other Commitment, Due Sixth Year Other Commitment, Due Seventh Year Other Commitment, Due Seventh Year Other Commitment, Due Seventh Year Other Commitment, Due Eighth Year Other Commitment, Due Eighth Year Other Commitment, Due Eight Year Other Commitment, Due Ninth Year Other Commitment, Due Ninth Year Other Commitment, Due Ninth Year Other Commitment, Due Tenth Year Other Commitment, Due Tenth Year Other Commitment, Due Tenth Year Subordinated Borrowing [Table] Subordinated Borrowing [Table] Subordinated Borrowing [Axis] Subordinated Borrowing [Axis] Subordinated Borrowing, Name [Domain] Subordinated Borrowing, Name [Domain] Junior Subordinated Deferrable Interest Debenture Issues by MWFC Junior Subordinated Deferrable Interest Debenture Issues by MWFC [Member] Junior Subordinated Deferrable Interest Debenture Issues by MWFC [Member] MWF Statutory Trust III MWF Statutory Trust III [Member] MWF Statutory Trust III [Member] MWF Statutory Trust IV MWF Statutory Trust IV [Member] MWF Statutory Trust IV [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] London Interbank Offered Rate (LIBOR) London Interbank Offered Rate (LIBOR) [Member] Subordinated Borrowing [Line Items] Subordinated Borrowing [Line Items] Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Interest Rate, Effective Percentage Debt Instrument, Interest Rate, Effective Percentage Statement of Comprehensive Income [Abstract] Other comprehensive income (loss), before tax: Other Comprehensive Income (Loss), before Tax [Abstract] Change in net unrealized gains/losses during period Reclassification adjustment for net (gains) losses included in income Defined benefit post-retirement benefits plans: Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract] Change in net actuarial loss Defined Benefit Plan, Actuarial Gain (Loss) Deferred tax benefit (expense) related to other comprehensive income Other comprehensive income (loss), net of tax Comprehensive income, net of tax Comprehensive Income (Loss), Net of Tax, Attributable to Parent Legal Proceedings [Abstract] Legal Proceedings [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Pending Litigation Pending Litigation [Member] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Kelly Logging Inc. v. First Interstate Bank Kelly Logging Inc. v. First Interstate Bank [Member] Kelly Logging Inc. v. First Interstate Bank [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Loss Contingency, Damages Awarded, Value Loss Contingency, Damages Awarded, Value Loss Contingency, Compensatory Damages Awarded, Value Loss Contingency, Compensatory Damages Awarded, Value Loss Contingency, Compensatory Damages Awarded, Value Loss Contingency, Punitive Damages Awarded, Value Loss Contingency, Punitive Damages Awarded, Value Loss Contingency, Punitive Damages Awarded, Value Loss Contingency Accrual Loss Contingency Accrual Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Loans and Leases Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Document and Entity Information [Abstract] Document and Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table] Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table] Business Acquisition, Equity Interests Issued or Issuable [Line Items] Business Acquisition, Equity Interests Issued or Issuable [Line Items] Transferred Loans to OREO SEC Schedule III, Real Estate, Acquisitions Through Foreclosures Transferred Loans to Mortgage Servicing Assets Transfer of Portfolio Loans to Mortgage Servicing Assets Transfer of Portfolio Loans to Mortgage Servicing Assets Transfer from Investments Transfer from Investments Land and buildings transferred to other assets Land and buildings transferred to other assets Land and buildings transferred to other assets Fair Value Measurements Fair Value Disclosures [Text Block] Commitments and Contingencies Disclosure [Abstract] Unrecorded Unconditional Purchase Obligation [Table] Unrecorded Unconditional Purchase Obligation [Table] Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Construction Contracts Construction Contracts [Member] Unrecorded Unconditional Purchase Obligation [Line Items] Unrecorded Unconditional Purchase Obligation [Line Items] Commitments to Purchase Unrecorded Unconditional Purchase Obligation Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of Financial Assets and Financial Liabilities Measured at Fair Value on a Non-Recurring Basis Fair Value Measurements, Nonrecurring [Table Text Block] Schedule of Estimated Fair Values of Financial Instruments by Level of Valuation Inputs Fair Value, by Balance Sheet Grouping [Table Text Block] Financial Instruments with Off-Balance Sheet Risk [Abstract] Financial Instruments with Off Balance Sheet Risk. Entities [Table] Entities [Table] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Standby Letters of Credit Financial Standby Letter of Credit [Member] Unused Credit Card Lines Unused Credit Card Lines [Member] Unused Credit Card Lines [Member] Entity Information [Line Items] Entity Information [Line Items] Credit Extension Commitments Credit Extension Commitments Credit Extension Commitments Credit Extension Commitments, Beyond One Year Credit Extension Commitments, Beyond One Year Credit Extension Commitments, Beyond One Year Investment Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Related Party Transactions Disclosure [Text Block] Related Party Transactions Disclosure [Text Block] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] FIB First Interstate Bank [Member] First Interstate Bank [Member] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Total risk-based capital: Capital [Abstract] Actual Amount Capital Actual Ratio Capital to Risk Weighted Assets Adequately Capitalized Amount Capital Required for Capital Adequacy Adequately Capitalized Ratio Capital Required for Capital Adequacy to Risk Weighted Assets Well Capitalized Amount Capital Required to be Well Capitalized Well Capitalized Ratio Capital Required to be Well Capitalized to Risk Weighted Assets Tier 1 risk-based capital: Tier One Risk Based Capital [Abstract] Actual Amount Tier One Risk Based Capital Actual Ratio Tier One Risk Based Capital to Risk Weighted Assets Adequately Capitalized Amount Tier One Risk Based Capital Required for Capital Adequacy Adequately Capitalized Ratio Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets Well Capitalized Amount Tier One Risk Based Capital Required to be Well Capitalized Well Capitalized Ratio Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets Leverage capital ratio: Tier One Leverage Capital [Abstract] Actual Amount Tier One Leverage Capital Actual Ratio Tier One Leverage Capital to Average Assets Adequately Capitalized Amount Tier One Leverage Capital Required for Capital Adequacy Adequately Capitalized Ratio Tier One Leverage Capital Required for Capital Adequacy to Average Assets Well Capitalized Amount Tier One Leverage Capital Required to be Well Capitalized Well Capitalized Ratio Tier One Leverage Capital Required to be Well Capitalized to Average Assets Financial Instruments with Off-Balance Sheet Risk Financial Instruments With Off Balance Sheet Risk [Text Block] Financial Instruments With Off Balance Sheet Risk. Common stock Common shares purchased and retired Common shares issued Stock Issued During Period, Shares, New Issues Non-vested common shares issued Stock Issued During Period, Shares, Restricted Stock Award, Gross Non-vested common shares forfeited Stock Issued During Period, Shares, Restricted Stock Award, Forfeited Stock options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Shares tendered in payment of option price and income tax withholding amounts Shares tendered in payment of option price and income tax withholding amounts, shares Shares tendered in payment of option price and income tax with holding amounts. Common (in dollars per share) Common Stock, Dividends, Per Share, Declared Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward] Beginning Balance Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Acquisition Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Additions Accretion Income Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion Reductions Due to Exit Events Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Disposals of Loans Ending Balance Other Real Estate Owned Real Estate Owned [Text Block] Net accumulated other comprehensive income: Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Net unrealized gain on investment securities available-for-sale Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Net actuarial loss on defined benefit post-retirement benefit plans Defined Benefit Plan, Accumulated Other Comprehensive Income Net Gains (Losses), after Tax Net accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Corporate Debt Securities [Member] Available-for-Sale: Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract] Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Less Than 12 months, Aggregate Loss1 Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Available-for-Sale, 12 Months or More Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, 12 months or Longer, Aggregate Loss1 Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Available-for-Sale, Total Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss1 Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Held-to-Maturity: Held-to-maturity Securities, Continuous Unrealized Loss Position [Abstract] Held-to-Maturity, Less than 12 Months Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Less Than 12 months, Aggregate Loss1 Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Held-to-Maturity, 12 Months or More Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Held-to-Maturity, 12 Months or More Gross Unrealized Losses Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Held-to-Maturity, Total Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss1 Held-to-maturity Securities, Continuous Unrealized Loss Position, Accumulated Loss Available-for-Sale and Held-to-Maturity: Available-for-Sale and Held-to-Maturity, Securities in Unrealized Loss Positions [Abstract] Available-for-Sale and Held-to-Maturity, Securities in Unrealized Loss Positions [Abstract] Investment Securities in an Unrealized Loss Position (Number of Securities) Available-for-Sale and Held-to-Maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Available-for-Sale and Held-to-Maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Common Stock Stockholders' Equity Note Disclosure [Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Statement of Financial Position [Abstract] Assets Assets [Abstract] Cash and due from banks Cash and Due from Banks Federal funds sold Federal Funds Sold Interest bearing deposits in banks Interest-bearing Deposits in Banks and Other Financial Institutions Total cash and cash equivalents Cash, Cash Equivalents, and Federal Funds Sold Investment securities: Marketable Securities [Abstract] Available-for-sale Held-to-maturity (estimated fair values of $588,032 and $205,926 at September 30, 2014 and December 31, 2013, respectively) Total investment securities Marketable Securities Mortgage loans held for sale Less allowance for loan losses Net loans Loans and Leases Receivable, Net Amount Goodwill Premises and equipment, net of accumulated depreciation Property, Plant and Equipment, Net Company-owned life insurance Bank Owned Life Insurance Other real estate owned (OREO) Real Estate Acquired Through Foreclosure Accrued interest receivable Interest Receivable Core deposit intangibles, net of accumulated amortization Core Deposit Intangibles Net Core deposit intangibles, net of accumulated amortization. Mortgage servicing rights, net of accumulated amortization and impairment reserve Servicing Asset at Amortized Cost Deferred tax asset, net Deferred Tax Assets, Net of Valuation Allowance Other assets Other Assets Total assets Assets Liabilities and Stockholders' Equity Liabilities and Equity [Abstract] Deposits: Deposits [Abstract] Non-interest bearing Noninterest-bearing Deposit Liabilities Interest bearing Interest-bearing Deposit Liabilities Total deposits Deposits Securities sold under repurchase agreements Securities Sold under Agreements to Repurchase Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities Accrued interest payable Interest Payable Long-term debt Other Long-term Debt Other borrowed funds Other Short-term Borrowings Subordinated debentures held by subsidiary trusts Total liabilities Liabilities Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; no shares issued and outstanding as of September 30, 2014 or December 31, 2013 Preferred Stock, Including Additional Paid in Capital Common stock Common Stocks, Including Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income, net Total stockholders' equity Total liabilities and stockholders' equity Liabilities and Equity Earnings per Common Share Earnings Per Share [Text Block] Investment securities: Held-to-maturity Securities, Parenthetical Disclosure [Abstract] Stockholders' equity: Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract] Nonvoting noncumulative preferred stock, par value Preferred Stock, No Par Value Nonvoting noncumulative preferred stock, authorized shares Preferred Stock, Shares Authorized Nonvoting noncumulative preferred stock, issued shares Preferred Stock, Shares Issued Nonvoting noncumulative preferred stock, outstanding shares Preferred Stock, Shares Outstanding Real Estate Acquired Through Foreclosure [Roll Forward] Real Estate Acquired Through Foreclosure [Roll Forward] Real Estate Acquired Through Foreclosure [Roll Forward] Beginning balance OREO Acquired Through Acquisition Real Estate Acquired Through Foreclosure, Acquired Through Acquisition Real Estate Acquired Through Foreclosure, Acquired Through Acquisition Additions Real Estate Acquired Through Foreclosure, Additions Real Estate Acquired Through Foreclosure, Additions Capitalized improvements Real Estate Acquired Through Foreclosure, Improvements Real Estate Acquired Through Foreclosure, Improvements Valuation adjustments Dispositions Real Estate Acquired Through Foreclosure, Disposals Real Estate Acquired Through Foreclosure, Disposals Ending balance