Equity [Abstract]
Investment securities available-for sale:
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, after Tax [Abstract]
Change in net unrealized gain during period, pre-tax
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, before Tax
Change in net unrealized gain during period, tax expense (benefit)
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax
Change in net unrealized gain during period, net of tax
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity, pre-tax
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, before Tax
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity, tax expense (benefit)
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Tax
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity, net of tax
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax
Defined benefits post-retirement benefit plan:
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract]
Change in net actuarial (gain) loss, pre-tax
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax
Change in net actuarial (gain) 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 (gain) loss, net of tax amount
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax
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
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax
Subsequent Events [Abstract]
Subsequent Event [Table]
Subsequent Event [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]
Subsequent Event Type [Axis]
Subsequent Event Type [Axis]
Subsequent Event Type [Domain]
Subsequent Event Type [Domain]
Subsequent Event
Subsequent Event [Member]
Subsequent Event [Line Items]
Subsequent Event [Line Items]
Dividend amount per share (in dollars)
Dividends Payable, Amount Per Share
Receivables [Abstract]
Schedule of Loans by Class
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]
Schedule of Recorded Investment in Past Due Loans by Class
Past Due Financing Receivables [Table Text Block]
Schedule of Acquired Loans with Credit Impairment
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Table Text Block]
Schedule of Recorded Investment in Impaired Loans
Impaired 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]
Document and Entity Information [Abstract]
Document and Entity Information [Abstract]
Statement [Table]
Statement [Table]
Class B Common Stock
Common Class B [Member]
Statement [Line Items]
Statement [Line Items]
Entity Registrant Name
Entity Registrant Name
Trading Symbol
Trading Symbol
Entity Central Index Key
Entity Central Index Key
Document Fiscal Year Focus
Document Fiscal Year Focus
Current Fiscal Year End Date
Current Fiscal Year End Date
Entity Filer Category
Entity Filer Category
Document Type
Document Type
Document Fiscal Period Focus
Document Fiscal Period Focus
Document Period End Date
Document Period End Date
Amendment Flag
Amendment Flag
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Entity Emerging Growth Company
Entity Emerging Growth Company
Entity Small Business
Entity Small Business
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative [Table]
Derivative [Table]
Hedging Designation [Axis]
Hedging Designation [Axis]
Hedging Designation [Domain]
Hedging Designation [Domain]
Designated as Hedging Instrument [Member]
Designated as Hedging Instrument [Member]
Not Designated as Hedging Instrument
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net
Amount of gain recognized in other non-interest income
Derivative, Gain (Loss) on Derivative, Net
Amount of net fee income recognized in other non-interest income
Fee Income on Derivatives
Fee Income on Derivatives
Amount of net gains recognized in mortgage banking revenues
Gain (Loss) on Fair Value Hedges Recognized in Earnings
Statement of Cash Flows [Abstract]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)
Repayments of Other Long-term Debt
Repayments of Other Long-term Debt
Cash flows from operating activities:
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income
Net Income (Loss) Attributable to Parent
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
Depreciation and amortization
Depreciation, Depletion and Amortization
Net premium amortization on investment securities
Accretion (Amortization) of Discounts and Premiums, Investments
Gain (Loss) on Sale of Debt Investments
Gain (Loss) on Sale of Debt Investments
Realized and unrealized net gains on mortgage banking activities
Gain (Loss) on Sale of Loans and Leases
Net gain on sale of OREO
Gains (Losses) on Sales of Other Real Estate
Asset Impairment Charges
Asset Impairment Charges
Proceeds From The Sale Of Health Savings Accounts
Proceeds From The Sale Of Health Savings Accounts
Proceeds From The Sale Of Health Savings Accounts
Mortgage servicing rights recovery
Mortgage Servicing Rights (MSR) Impairment (Recovery)
Deferred tax expenses
Deferred Income Tax Expense (Benefit)
Net increase in cash surrender value of company-owned life insurance
Life Insurance, Corporate or Bank Owned, Change in Value
Stock-based compensation expense
Share-based Compensation
Originations of mortgage loans held for sale
Payments for Origination of Mortgage Loans Held-for-sale
Proceeds from sales of mortgage loans held for sale
Proceeds from Sale of Mortgage Loans Held-for-sale
Changes in operating assets and liabilities, net of effects of acquisition:
Increase (Decrease) in Operating Capital [Abstract]
Increase in interest receivable
Increase (Decrease) in Accrued Interest Receivable, Net
(Increase) decrease in other assets
Increase (Decrease) in Other Operating Assets
Increase 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]
Purchase of investment securities, Held-to-maturity
Payments to Acquire Held-to-maturity Securities
Purchase of investment securities, Available-for-sale
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 Debt Securities, Available-for-sale
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 sale of OREO
Proceeds from Sale of Wholly Owned Real Estate and Real Estate Acquired in Settlement of Loans
Acquisition of intangible assets
Payments to Acquire Intangible Assets
Proceeds from the sale of Health Savings Accounts
Proceeds from Sale of Productive Assets
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 provided by (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) increase in securities sold under repurchase agreements
Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase
Net decrease in other borrowed funds
Proceeds from (Repayments of) Short-term Debt
Advances on long-term debt
Proceeds from Issuance of Long-term Debt
Proceeds from issuance of common stock
Proceeds from Issuance of Common Stock
Purchase and retirement of common stock
Payments for Repurchase 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 increases (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, Including Capitalized Interest, Operating and Investing Activities
Supplemental schedule of noncash investing activities from acquisitions:
Noncash or Part Noncash Acquisition, Net Nonmonetary Assets Acquired (Liabilities Assumed) [Abstract]
Noncash or Part Noncash Acquisition, Value of Assets Acquired [Abstract]
Noncash or Part Noncash Acquisition, Value of Assets Acquired [Abstract]
Transfer of loans to loans held for sale
Transfer of Portfolio Loans and Leases to Held-for-sale
Transfer of loans to other real estate owned
Real Estate Owned, Transfer to Real Estate Owned
Capitalization of internally originated mortgage servicing rights
Capitalization Of Internally Originated Mortgage Servicing Rights, Noncash Supplemental Disclosures
Capitalization Of Internally Originated Mortgage Servicing Rights, Noncash Supplemental Disclosures
Noncash or Part Noncash Acquisition, Investments Acquired
Noncash or Part Noncash Acquisition, Investments Acquired
Noncash Or Part Noncash Acquisition, HTM Investments Acquired
Noncash Or Part Noncash Acquisition, HTM Investments Acquired
Noncash Or Part Noncash Acquisition, HTM Investments Acquired
Noncash Or Part Noncash Acquisition, Loans Held For Sale Acquired
Noncash Or Part Noncash Acquisition, Loans Held For Sale Acquired
Noncash Or Part Noncash Acquisition, Loans Held For Sale Acquired
Noncash Or Part Noncash Acquisition, Loans Acquired
Noncash Or Part Noncash Acquisition, Loans Acquired
Noncash Or Part Noncash Acquisition, Loans Acquired
Noncash or Part Noncash Acquisition, Fixed Assets Acquired
Noncash or Part Noncash Acquisition, Fixed Assets Acquired
Noncash Or Part Noncash Acquisition, Goodwill
Noncash Or Part Noncash Acquisition, Goodwill
Noncash Or Part Noncash Acquisition, Goodwill
Noncash or Part Noncash Acquisition, Intangible Assets Acquired
Noncash or Part Noncash Acquisition, Intangible Assets Acquired
Noncash Or Part Noncash Acquisition, Mortgage Servicing Asset Acquired
Noncash Or Part Noncash Acquisition, Mortgage Servicing Asset Acquired
Noncash Or Part Noncash Acquisition, Mortgage Servicing Asset Acquired
Noncash Or Part Noncash Acquisition, Interest Receivable Acquired
Noncash Or Part Noncash Acquisition, Interest Receivable Acquired
Noncash Or Part Noncash Acquisition, Interest Receivable Acquired
Noncash Or Part Noncash Acquisition, Company-Owned Life Insurance Acquired
Noncash Or Part Noncash Acquisition, Company-Owned Life Insurance Acquired
Noncash Or Part Noncash Acquisition, Company-Owned Life Insurance Acquired
Noncash Or Part Noncash Acquisition, Deferred Tax Assets Acquired
Noncash Or Part Noncash Acquisition, Deferred Tax Assets Acquired
Noncash Or Part Noncash Acquisition, Deferred Tax Assets Acquired
Noncash Or Part Noncash Acquisition, Other Real Estate Owned Acquired
Noncash Or Part Noncash Acquisition, Other Real Estate Owned Acquired
Noncash Or Part Noncash Acquisition, Other Real Estate Owned Acquired
Noncash or Part Noncash Acquisition, Other Assets Acquired
Noncash or Part Noncash Acquisition, Other Assets Acquired
Noncash or Part Noncash Acquisition, Value of Assets Acquired
Noncash or Part Noncash Acquisition, Value of Assets Acquired
Noncash Or Part Noncash Acquisition, Deposits Acquired
Noncash Or Part Noncash Acquisition, Deposits Acquired
Noncash Or Part Noncash Acquisition, Deposits Acquired
Noncash or Part Noncash Acquisition, Debt Assumed
Noncash or Part Noncash Acquisition, Debt Assumed
Noncash or Part Noncash Acquisition, Other Liabilities Assumed
Noncash or Part Noncash Acquisition, Other Liabilities Assumed
Noncash or Part Noncash Acquisition, Trust Preferred Securities Assumed
Noncash or Part Noncash Acquisition, Trust Preferred Securities Assumed
Noncash or Part Noncash Acquisition, Trust Preferred Securities Assumed
Noncash or Part Noncash Acquisition, Deferred Tax Liability
Noncash or Part Noncash Acquisition, Deferred Tax Liability
Noncash or Part Noncash Acquisition, Deferred Tax Liability
Noncash or Part Noncash Acquisition, Payables Assumed
Noncash or Part Noncash Acquisition, Payables Assumed
Noncash or Part Noncash Acquisition, Value of Liabilities Assumed
Noncash or Part Noncash Acquisition, Value of Liabilities Assumed
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles
Goodwill and Intangible Assets Disclosure [Text Block]
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation
Business Description and Basis of Presentation [Text Block]
Schedule of Impaired Financing Receivable [Table]
Schedule of Impaired Financing Receivable [Table]
Class of Financing Receivable, Type [Axis]
Class of Financing Receivable, Type [Axis]
Class of Financing Receivable, Type [Domain]
Class of Financing Receivable, Type [Domain]
Commercial
Commercial Real Estate Portfolio Segment [Member]
Land acquisition & development
Land Acquisition & Development Construction Financing Receivable [Member]
Land Acquisition & Development Construction Financing Receivable [Member]
Residential
Residential Real Estate Construction Financing Receivable [Member]
Residential Real Estate Construction Financing Receivable [Member]
Commercial
Commercial Real Estate Construction [Member]
Commercial Real Estate Construction Member [Member]
Total construction loans
Real Estate Construction Financing Receivable [Member]
Real Estate Construction Financing Receivable [Member]
Residential
Residential Mortgage [Member]
Agricultural
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]
Total consumer loans
Consumer Portfolio Segment [Member]
Commercial
Commercial Portfolio Segment [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
Related Allowance
Impaired Financing Receivable, Related Allowance
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment
Impaired Financing Receivable, Average Recorded Investment
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Impaired Financing Receivable, Interest Income, Cash Basis Method [Abstract]
Income Recognized
Impaired Financing Receivable, Interest Income, Cash Basis Method
Capital Stock
Stockholders' Equity Note Disclosure [Text Block]
Deteriorated Loans Transferred in [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table]
Schedule of Business Acquisitions, by Acquisition [Table]
Business Acquisition [Axis]
Business Acquisition [Axis]
Business Acquisition, Acquiree [Domain]
Business Acquisition, Acquiree [Domain]
Inland Northwest Bank
Inland Northwest Bank [Member]
Inland Northwest Bank [Member]
Bank of the Cascades
Bank of the Cascades [Member]
Bank of the Cascades [Member]
Business Acquisition [Line Items]
Business Acquisition [Line Items]
Contractually required principal and interest payments
Loans Acquired in Transfer, Contractually Required Payments Receivable at Acquisition
Loans Acquired in Transfer, Contractually Required Payments Receivable at Acquisition
Contractual cash flows not expected to be collected
Loans Acquired in Transfer, Nonaccretable Difference
Loans Acquired in Transfer, Nonaccretable Difference
Fair value at acquisition
Loans Acquired in Transfer at Acquisition Fair Value
Loans Acquired in Transfer at Acquisition Fair Value
Business Combinations [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 (“non-accretable discount”)
Certain Loans Acquired in Transfer, Nonaccretable Difference
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 (“accretable discount”)
Certain Loans Acquired in Transfer, Accretable Yield
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
Idaho Independent Bank [Member]
Idaho Independent Bank [Member]
Idaho Independent Bank [Member]
Northwest Bank Acquisition, as Recorded by the Company [Member]
Northwest Bank Acquisition, as Recorded by the Company [Member]
Northwest Bank Acquisition, as Recorded by the Company [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
Core Deposits [Member]
Legal Entity [Axis]
Legal Entity [Axis]
Entity [Domain]
Entity [Domain]
Revenues
Revenues
Pro Forma Acquisition Expenses, Net of Tax
Pro Forma Acquisition Expenses, Net of Tax
Pro Forma Acquisition Expenses, Net of Tax
Core deposit intangible assets
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles
Number of banking offices acquired
Number Of Banking Offices Acquired
Number Of Banking Offices Acquired
Estimate of Payments to Acquire Businesses, Gross
Estimate of Payments to Acquire Businesses, Gross
Estimate of Payments to Acquire Businesses, Gross
Estimate value per share of Acquisition
Estimate value per share of Acquisition
Estimate value per share of Acquisition
Business acquisition conversion share rate
Business Acquisition Conversion Share Rate
Business Acquisition Conversion Share Rate
Business acquisition cash conversion amount (in dollars per share)
Business Acquisition, Conversion Rate
Business Acquisition, Conversion Rate
Number of shares issued in connection with Cascade merger
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares
Price per share of First Interstate Class A common stock (in dollars per share)
Business Acquisition, Share Price
Cash Paid For Northwest Warrants
Cash Paid For Northwest Warrants
Cash Paid For Northwest Warrants
Cash paid by First Interstate in connection with merger
Payments to Acquire Businesses, Gross
Total consideration exchanged in connection with the merger
Business Combination, Consideration Transferred
Cash Paid Related To Cascade Options
Cash Paid Related To Cascade Options
Cash Paid Related To Cascade Options
Cash Paid For Cascade Unvested Restricted Stock
Cash Paid For Cascade Unvested Restricted Stock
Cash Paid For Cascade Unvested Restricted Stock
Shares Issued For Cascade Unvested Restricted Stock
Shares Issued For Cascade Unvested Restricted Stock
Shares Issued For Cascade Unvested Restricted Stock
Expense related to restricted awards excluded from consideration
Expense related to restricted awards excluded from consideration
Expense related to restricted awards excluded from consideration
Restricted stock expense included in consideration
Restricted stock expense included in consideration
Restricted stock expense included in consideration
Goodwill
Goodwill
Number of operating segments
Number of Operating Segments
Estimated useful lives of related deposits
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life
Acquisition related expenses
Business Combination, Acquisition Related Costs
Net income
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities [Abstract]
Outstanding balance
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance
Loans on 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
Total carrying value
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net
Loans
Financing Receivables [Text Block]
Finite-lived Intangible Assets Acquired
Finite-lived Intangible Assets Acquired
Finite-Lived Intangible Assets, Period Increase (Decrease)
Finite-Lived Intangible Assets, Period Increase (Decrease)
Goodwill [Roll Forward]
Goodwill [Roll Forward]
CDI, net, beginning of period
Finite-Lived Intangible Assets, Net
CDI current period amortization
Amortization of Intangible Assets
Total CDI, net, at September 30
Statement of Financial Position [Abstract]
Investment securities:
Debt Securities, Held-to-maturity, Parenthetical Disclosure [Abstract]
Estimated fair value
Debt Securities, Held-to-maturity, Fair Value
Stockholders' equity:
Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract]
Nonvoting, noncumulative preferred stock, shares authorized
Preferred Stock, Shares Authorized
Nonvoting, noncumulative preferred stock, shares issued
Preferred Stock, Shares Issued
Nonvoting, noncumulative preferred stock, shares outstanding
Preferred Stock, Shares Outstanding
Accounting Policies [Abstract]
Recent Authoritative Accounting Guidance
New Accounting Pronouncements and Changes in Accounting Principles [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]
Banking and Thrift [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]
Financial Instruments with Off-Balance Sheet Risk [Abstract]
Financial Instruments with Off Balance Sheet Risk.
Financial Instruments with Off-Balance Sheet Risk
Financial Instruments With Off Balance Sheet Risk [Text Block]
Financial Instruments With Off Balance Sheet Risk.
Interest income
Business Acquisition, Pro Forma Interest Income
Business Acquisition, Pro Forma Interest Income
Non-interest income
Business Acquisition, Pro Forma Non Interest Income
Business Acquisition, Pro Forma Non Interest Income
Total revenues
Business Acquisition, Pro Forma Revenue
Net income
Business Acquisition, Pro Forma Net Income (Loss)
EPS - basic (in dollars per share)
Business Acquisition, Pro Forma Earnings Per Share, Basic
EPS - diluted (in dollars per share)
Business Acquisition, Pro Forma Earnings Per Share, Diluted
Statement of Stockholders' Equity [Abstract]
New Accounting Pronouncement, Early Adoption [Axis]
New Accounting Pronouncement, Early Adoption [Axis]
New Accounting Principles, Early Adoption [Domain]
New Accounting Principles, Early Adoption [Domain]
ASU 2018-02
ASU 2018-02 [Member]
ASU 2018-02 [Member]
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 (loss)
AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance
Stockholders' Equity Attributable to Parent
Reclassification of the income tax effects of the Tax Cut and Jobs Act from AOCI
Reclassifications Of Income Tax Effects
Reclassifications Of Income Tax Effects
Other comprehensive income, net of tax expense
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
Stock Repurchased and Retired During Period, Value
Stock Issued During Period, Value, New Issues
Stock Issued During Period, Value, New Issues
Stock options exercised, net of shares tendered in payment of option price and income tax withholding amounts
Stock Issued During Period, Value, Stock Options Exercised
Stock-based compensation expense
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition
Common cash dividend declared
Dividends, Common Stock, Cash
Ending Balance
Other Comprehensive Income/Loss
Comprehensive Income (Loss) Note [Text Block]
Net accumulated other comprehensive income:
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net unrealized gain (loss) on investment securities available-for-sale
Accumulated Other Comprehensive Income (Loss), Debt Securities, Available-for-sale, Adjustment, after Tax
Net unrealized gain (loss) on derivatives
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax
Net actuarial gain (loss) on defined benefit post-retirement benefit plans
Accumulated Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Tax
Net accumulated other comprehensive gain (loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax
New Accounting Pronouncements or Change in Accounting Principle [Table]
New Accounting Pronouncements or Change in Accounting Principle [Table]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Schedule of Financing Receivable, Troubled Debt Restructurings [Table]
Schedule of Financing Receivable, Troubled Debt Restructurings [Table]
Loan Restructuring Modification [Axis]
Loan Restructuring Modification [Axis]
Loan Restructuring Modification [Domain]
Loan Restructuring Modification [Domain]
Interest Only Period Concession [Member]
Interest Only Period Concession [Member]
Interest Only Period Concession [Member]
Extended Maturity [Member]
Extended Maturity [Member]
Contractual Interest Rate Reduction [Member]
Contractual Interest Rate Reduction [Member]
Other Concession [Member]
Other Concession [Member]
Other Concession [Member]
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts
Financing Receivable, Modifications, Number of Contracts
Financing Receivable, Modifications, Post-Modification Recorded Investment
Financing Receivable, Modifications, Post-Modification Recorded Investment
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
Loans restructured during period
Financing Receivable, Modifications, Pre-Modification Recorded Investment
Charge-offs directly related to modifying troubled debt restructurings
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down
Balance of defaulted loans under trouble debt restructurings
Financing Receivable, Modifications, Subsequent Default, Recorded Investment
Commitments to lend additional funds
Loans and Leases Receivable, Impaired, Commitment to Lend
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Acquired
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Acquired
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Acquired
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Additions
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Additions
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
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
Reclassifications from nonaccretable differences
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications (to) from Nonaccretable Difference
Ending Balance
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
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping [Table]
Fair Value, by Balance Sheet Grouping [Table]
Fair Value Hierarchy and NAV [Axis]
Fair Value Hierarchy and NAV [Axis]
Fair Value, Measurements, Fair Value Hierarchy [Domain]
Fair Value Hierarchy and NAV [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]
Measurement Basis [Axis]
Measurement Basis [Axis]
Fair Value Measurement [Domain]
Fair Value Measurement [Domain]
Portion at Fair Value Measurement
Portion at Fair Value Measurement [Member]
Carrying Amount
Reported Value Measurement [Member]
Estimated Fair Value
Estimate of Fair Value Measurement [Member]
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 debt securities available-for-sale:
Available-for-sale Securities
Investment debt securities held-to-maturity
Accrued interest receivable
Accrued Interest Receivable, Fair Value Disclosure
Accrued Interest Receivable, Fair Value Disclosure
Mortgage servicing rights, net
Servicing Asset at Fair Value, Amount
Loans held for sale
Mortgages Held-for-sale, Fair Value Disclosure
Net loans held for investment
Loans Receivable, Fair Value Disclosure
Impaired loans
Loans Receivable, Impaired, Fair Value Disclosure
Loans Receivable, Impaired, Fair Value Disclosure
Derivative assets
Derivative Asset
Deferred compensation plan assets
Deferred compensation asset at fair value amount
Deferred compensation asset at fair value amount
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
Derivative liabilities
Derivative Liability
Deferred compensation plan liabilities
Deferred compensation plan liabilities at fair value amount
Deferred compensation plan liabilities at fair value amount
Total financial liabilities
Financial and Nonfinancial Liabilities, Fair Value Disclosure
Regulatory Capital
Regulatory Capital Requirements under Banking Regulations [Text Block]
Schedule of Goodwill [Table]
Schedule of Goodwill [Table]
Consolidation Items [Axis]
Consolidation Items [Axis]
Consolidation Items [Domain]
Consolidation Items [Domain]
Segments [Axis]
Segments [Axis]
Segments [Domain]
Segments [Domain]
Income Statement Location [Axis]
Income Statement Location [Axis]
Income Statement Location [Domain]
Income Statement Location [Domain]
Range [Axis]
Range [Axis]
Range [Domain]
Range [Domain]
Goodwill [Line Items]
Goodwill [Line Items]
Schedule of Goodwill [Table Text Block]
Schedule of Goodwill [Table Text Block]
Schedule of Finite-Lived Intangible Assets
Schedule of Finite-Lived Intangible Assets [Table Text Block]
Schedule of Future Amortization Expense
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
Entities [Table]
Entities [Table]
Guarantor Obligations, Nature [Axis]
Guarantor Obligations, Nature [Axis]
Guarantor Obligations, Nature [Domain]
Guarantor Obligations, Nature [Domain]
Unused Credit Card Lines
Unused Credit Card Lines [Member]
Unused Credit Card Lines [Member]
Standby Letters of Credit
Financial Standby Letter of Credit [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
Other Real Estate Owned
Real Estate Owned [Text Block]
Investments, Debt and Equity Securities [Abstract]
Investment Securities
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]
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]
Fair Value Inputs, Assets, Quantitative Information
Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]
Fair Value, by Balance Sheet Grouping
Fair Value, by Balance Sheet Grouping [Table Text Block]
Income Statement [Abstract]
Restatement [Axis]
Restatement [Axis]
Restatement [Domain]
Restatement [Domain]
Product and Service [Axis]
Product and Service [Axis]
Product and Service [Domain]
Product and Service [Domain]
Credit and Debit Card [Member]
Credit and Debit Card [Member]
Investment Advisory, Management and Administrative Service [Member]
Investment Advisory, Management and Administrative Service [Member]
Deposit Account [Member]
Deposit Account [Member]
Financial Service, Other [Member]
Financial Service, Other [Member]
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
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 other debt
Interest Expense, Other Long-term Debt
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
Provision for Loan and Lease Losses
Net interest income after provision for loan losses
Interest Income (Expense), after Provision for Loan Loss
Non-interest income:
Noninterest Income [Abstract]
Payment services revenues
Revenue from Contract with Customer, Excluding Assessed Tax
Gain (Loss) on Termination of Interest Rate Swap
Gain (Loss) on Termination of Interest Rate Swap
Gain (Loss) on Termination of Interest Rate Swap
Mortgage banking revenues
Fees and Commissions, Mortgage Banking and Servicing
Wealth management revenues
Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions
Investment securities gains (losses), net
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
Outsourced technology services
Information Technology and Data Processing
Occupancy, net
Occupancy, Net
Furniture and equipment
Equipment Expense
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 recovery
Core deposit intangibles amortization
Other expenses
Other Noninterest Expense
Total non-interest expense
Noninterest Expense
Income tax expense
Income Tax Expense (Benefit)
Net income
Basic earnings per common share (in dollars per share)
Earnings Per Share, Basic
Diluted earnings per common share (in dollars per share)
Earnings Per Share, Diluted
Weighted average common shares outstanding for basic earnings per share computation
Weighted Average Number of Shares Outstanding, Basic
Weighted Average Number of Shares Outstanding, Diluted
Weighted Average Number of Shares Outstanding, Diluted
Common stock
Common shares purchased and retired
Stock Repurchased and Retired During Period, Shares
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 (in shares)
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 dividends (in dollars per share)
Common Stock, Dividends, Per Share, Declared
Amortized Cost and Approximate Fair Values of Investment Securities
Marketable Securities [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]
Addition to provisional goodwill from acquisition
Goodwill, Acquired During Period
Measurement period adjustment to previously recorded goodwill
Goodwill, Purchase Accounting Adjustments
Impairment of goodwill
Goodwill, Impairment Loss
Weighted average useful lives of related deposits
Assets
Assets [Abstract]
Cash and due from banks
Cash and Due from Banks
Interest bearing deposits in banks
Interest-bearing Deposits in Banks and Other Financial Institutions
Federal Funds Sold
Federal Funds Sold
Total cash and cash equivalents
Cash, Cash Equivalents, and Federal Funds Sold
Investment securities:
Marketable Securities [Abstract]
Available-for-sale
Debt Securities, Available-for-sale
Held-to-maturity (estimated fair values of $407.4 and $483.3 at September 30, 2018 and December 31, 2017, respectively)
Debt Securities, Held-to-maturity
Total investment securities
Marketable Securities
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.
Mortgage loans held for sale
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage
Total loans
Loans and Leases Receivable, Gross
Less allowance for loan losses
Loans and Leases Receivable, Allowance
Net loans
Loans and Leases Receivable, Net Amount
Company-owned life insurance
Bank Owned Life Insurance
Premises and equipment, net of accumulated depreciation
Property, Plant and Equipment, Net
Accrued interest receivable
Interest Receivable
Mortgage servicing rights, net of accumulated amortization and impairment reserve
Servicing Asset at Amortized Cost
Core deposit intangibles, net of accumulated amortization
Core Deposit Intangibles Net
Core deposit intangibles, net of accumulated amortization.
Other real estate owned (“OREO”)
Real Estate Acquired Through Foreclosure
Deferred tax asset, net
Deferred Income Tax Assets, Net
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
Deferred tax liability, net
Deferred Income Tax Liabilities, Net
Long-term debt
Other Long-term Debt
Other borrowed funds
Other Short-term Borrowings
Subordinated debentures held by subsidiary trusts
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust
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, 2018 or December 31, 2017
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 loss, net
Total stockholders’ equity
Total liabilities and stockholders’ equity
Liabilities and Equity
Earnings Per Share [Abstract]
Earnings per Common Share
Earnings Per Share [Text Block]
Fair Value Measurement Inputs and Valuation Techniques [Table]
Fair Value Measurement Inputs and Valuation Techniques [Table]
Measurement Input Type [Axis]
Measurement Input Type [Axis]
Measurement Input Type [Domain]
Measurement Input Type [Domain]
Measurement Input, Discount Rate [Member]
Measurement Input, Discount Rate [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 Non-recurring Basis
Fair Value, Measurements, Nonrecurring [Member]
Minimum
Minimum [Member]
Maximum
Maximum [Member]
Weighted Average
Weighted Average [Member]
Valuation Approach and Technique [Axis]
Valuation Approach and Technique [Axis]
Valuation Approach and Technique [Domain]
Valuation Approach and Technique [Domain]
Market Approach Valuation Technique
Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate for Assets HFS Level 3 Fair Value
Discount Rate for Assets HFS Level 3 Fair Value
Discount Rate for Assets HFS Level 3 Fair Value
Discount Rate for OREO Level 3 Fair Value
Discount Rate for OREO Level 3 Fair Value
Discount Rate for OREO Level 3 Fair Value
Discount Rate for Level 3 Fair Value Disclosure
Discount Rate for Level 3 Fair Value Disclosure
Discount Rate for Impaired Loans Level 3 Fair Value
Net loans held for investment
Other real estate owned
Real Estate Acquired Through Foreclosure, Fair Value Disclosure
Real Estate Acquired Through Foreclosure, Fair Value Disclosure
Write downs on OREO properties
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Write-down or Reserve, Amount
Fair Value of long-lived assets to be disposed of by sale
Assets Held-for-sale, Long Lived, Fair Value Disclosure
Derivative Instrument [Axis]
Derivative Instrument [Axis]
Derivative Contract [Domain]
Derivative Contract [Domain]
Interest Rate Swap
Interest Rate Swap [Member]
Mortgage Related Derivatives
Mortgage Related Derivatives [Member]
Mortgage Related Derivatives [Member]
Derivative Asset, Gross Amounts Recognized
Derivative Asset, Fair Value, Gross Asset
Derivative Asset, Gross Amounts Offset in the Balance Sheet
Derivative Asset, Fair Value, Gross Liability
Derivative Asset, Net Amounts in the Balance Sheet
Derivative Asset, Fair Value, Amount Not Offset Against Collateral
Derivative Asset, Financial Instruments
Derivative Asset, Netting Adjustment Per Applicable Master Netting Agreements
Derivative Asset, Netting Adjustment Per Applicable Master Netting Agreements
Derivative Asset, Fair Value of Financial Collateral in the Balance Sheet
Derivative, Collateral, Obligation to Return Cash
Derivative Asset, Net Amount
Derivative Asset, Fair Value, Amount Offset Against Collateral
Total assets, Gross Amounts Recognized
Total Assets, Fair Value, Gross Asset
Total Assets, Fair Value, Gross Asset
Total assets, Gross Amounts Offset in the Balance Sheet
Total Assets, Fair Value, Gross Liability
Total Assets, Fair Value, Gross Liability
Total assets, Net Amounts in the Balance Sheet
Total Assets, Fair Value, Amount Not Offset Against Collateral
Total Assets, Fair Value, Amount Not Offset Against Collateral
Total assets, Financial Instruments
Total Asset Netting Adjustment Per Applicable Master Netting Arrangements
Total Asset Netting Adjustment Per Applicable Master Netting Arrangements
Total assets, Fair Value of Financial Collateral in the Balance Sheet
Total Collateral, Obligation To Return Cash
Total Collateral, Obligation To Return Cash
Total assets, Net Amount
Total Asset, Fair Value, Amount Offset Against Collateral
Total Asset, Fair Value, Amount Offset Against Collateral
Derivative liability, Gross Amounts Recognized
Derivative Liability, Fair Value, Gross Liability
Derivative liability, Gross Amounts Offset in the Balance Sheet
Derivative Liability, Fair Value, Gross Asset
Derivative liability, Net Amounts in the Balance Sheet
Derivative Liability, Fair Value, Amount Not Offset Against Collateral
Derivative liability, Financial Instruments
Derivative Liability, Netting Adjustment Per Applicable Master Netting Agreements
Derivative Liability, Netting Adjustment Per Applicable Master Netting Agreements
Derivative liability, Fair Value of Financial Collateral in the Balance Sheet
Derivative, Collateral, Right to Reclaim Cash
Derivative liability, Net Amount
Derivative Liability, Fair Value, Amount Offset Against Collateral
Repurchase agreements, Gross Amounts Recognized
Securities Sold under Agreements to Repurchase, Fair Value of Collateral
Repurchase agreements, Gross Amounts Offset in the Balance Sheet
Securities Sold under Agreements to Repurchase, Gross
Repurchase agreements, Net Amounts in the Balance Sheet
Securities Sold under Agreements to Repurchase, Not Offset, Policy Election Deduction
Repurchase agreements, Financial Instruments
Securities Sold Under Agreement To Repurchase Amount Not Offset Against Collateral
Securities Sold Under Agreement To Repurchase Amount Not Offset Against Collateral
Repurchase agreements, Fair Value of Financial Collateral in the Balance Sheet
Securities Purchased under Agreements to Resell, Collateral, Obligation to Return Securities
Repurchase agreements, Net Amount
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral
Total liabilities, Gross Amounts Recognized
Total Liabilities, Fair Value, Gross Amount
Total Liabilities, Fair Value, Gross Amount
Total liabilities, Gross Amounts Offset in the Balance Sheet
Total Liabilities, Fair Value, Gross Liability
Total Liabilities, Fair Value, Gross Liability
Total liabilities, Net Amounts in the Balance Sheet
Total Liabilities, Fair Value, Amount Not Offset Against Collateral
Total Liabilities, Fair Value, Amount Not Offset Against Collateral
Total liabilities, Financial Instruments
Total Liabilities, Netting Adjustment Per Applicable Master Netting Arrangements
Total Liabilities, Netting Adjustment Per Applicable Master Netting Arrangements
Total liabilities, Fair Value of Financial Collateral in the Balance Sheet
Total Collateral, Obligation To Return Cash Or Securities
Total Collateral, Obligation To Return Cash Or Securities
Total liabilities, Net Amount
Total Liabilities, Fair Value Amount Offset Against Collateral
Total Liabilities, Fair Value Amount Offset Against Collateral
Schedule of Stock by Class [Table]
Schedule of Stock by Class [Table]
Class of Stock [Line Items]
Class of Stock [Line Items]
Common stock outstanding (in shares)
Common Stock, Shares, Outstanding
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares
Class A common stock
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned
Stock repurchased and retired (in shares)
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
Northwest Bank Acquisition, As Recorded By Inland Northwest Bank [Member]
Northwest Bank Acquisition, As Recorded By Inland Northwest Bank [Member]
Northwest Bank Acquisition, As Recorded By Inland Northwest Bank
Northwest Bank Acquisition, Fair Value Adjustments [Member]
Northwest Bank Acquisition, Fair Value Adjustments [Member]
Northwest Bank Acquisition, Fair Value Adjustments [Member]
Cascade Bank Acquisition, As Recorded By Cascade Bank [Member]
Cascade Bank Acquisition, As Recorded By Cascade Bank [Member]
Cascade Bank Acquisition, As Recorded By Cascade Bank [Member]
Cascade Bank Acquisition, Fair Value Adjustments [Member]
Cascade Bank Acquisition, Fair Value Adjustments [Member]
Cascade Bank Acquisition, Fair Value Adjustments [Member]
Cascade Bank Acquisition, as Recorded by the Company [Member]
Cascade Bank Acquisition, as Recorded by the Company [Member]
Cascade Bank Acquisition, as Recorded by the 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 held for investment
Business Combinations, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Held for Investment
Business Combinations, Recognized Identifiable Assets Acquired and Liabilities Assumed, Loans Held for Investment
Mortgage loans held for sale
Business Combinations, Recognized Identifiable Assets Acquired And Liabilities Assumed, Loans Held For Sale
Business Combinations, Recognized Identifiable Assets Acquired And Liabilities Assumed, Loans Held For Sale
Allowance for loan loss
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
Other real estate owned (“OREO”)
Business Combinations Recognized Identifiable Assets Acquired And Liabilities Assumed Other Real Estate Owned
Business Combinations Recognized Identifiable Assets Acquired And Liabilities Assumed Other Real Estate Owned
Deferred tax assets, net
Business Combinations, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Asset
Business Combinations, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Asset
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
Accounts Payable and Accrued Expense
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Liabilities
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Liabilities
Long term debt
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt
Trust preferred securities
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Trust Preferred Securities
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Trust Preferred Securities
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
Cash
Total consideration paid
Net increase to goodwill
Interest Income on Non-Accrual Loans if Accrued
Allowance for Loan Losses
Allowance for Credit Losses [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]
Land acquisition & development
Residential
Indirect consumer
Consumer Indirect Financing Receivable [Member]
Consumer Indirect Financing Receivable [Member]
Other consumer
Consumer Loan [Member]
Credit card
Credit Card Receivable [Member]
Loans and Leases Receivable Recorded Investment, Criticized Loans [Line Items]
Financing Receivable, Recorded Investment [Line Items]
Fair Value Measurements
Fair Value Disclosures [Text Block]
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]
Financial Instrument [Axis]
Financial Instrument [Axis]
Financial Instruments [Domain]
Financial Instruments [Domain]
U.S. Treasury notes
US Treasury Securities [Member]
Obligations of U.S. government agencies
US Government Agencies Debt Securities [Member]
Private mortgage-backed securities
Mortgage-backed Securities, Issued by Private Enterprises [Member]
State, county and municipal securities
US States and Political Subdivisions Debt Securities [Member]
Corporate securities
Corporate Debt Securities [Member]
Other investments
Other Debt Obligations [Member]
Other Investments
Other Investments [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:
Debt Securities, Available-for-sale [Abstract]
Amortized Cost
Debt Securities, Available-for-sale, Amortized Cost
Gross Unrealized Gains
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax
Gross Unrealized Losses
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax
Estimated Fair Value
Held-to-Maturity:
Debt Securities, Held-to-maturity [Abstract]
Amortized Cost
Gross Unrealized Gains
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain
Gross Unrealized Losses
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss
Estimated Fair Value
Schedule of Notional Amounts and Estimated Fair Values of Derivatives
Schedule of Interest Rate Derivatives [Table Text Block]
Offsetting Assets and Liabilities
Offsetting Assets and Liabilities [Table Text Block]
Offsetting Assets and Liabilities [Table Text Block]
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block]
Schedule of Financing Receivables Past Due [Table]
Schedule of Financing Receivables Past Due [Table]
Financing Receivables, Period Past Due [Axis]
Financing Receivables, Period Past Due [Axis]
Financing Receivables, Period Past Due [Domain]
Financing Receivables, Period Past Due [Domain]
30 to 59 Days Past Due
Financing Receivables, 30 to 59 Days Past Due [Member]
60 to 89 Days Past Due
Financing Receivables, 60 to 89 Days Past Due [Member]
Equal to Greater than 90 Days Past Due
Financing Receivables, Equal to Greater than 90 Days Past Due [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]
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
Total Loans
Mortgage loans held for sale
Computation of Basic and Diluted Earnings per Share
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
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]
Commitments and Contingencies Disclosure [Abstract]
Loss Contingencies [Table]
Loss Contingencies [Table]
Other Commitments [Axis]
Other Commitments [Axis]
Other Commitments [Domain]
Other Commitments [Domain]
Construction Contracts
Construction Contracts [Member]
Mortgage Loans Held for Sale
Loss Contingencies [Line Items]
Loss Contingencies [Line Items]
Notional amount of terminated commitment
Derivative Liability, Notional Amount
Commitments under construction contracts
Other Commitment
Price per share (in dollars per share)
Mortgage loans with recourse provision in effect
Guarantor Obligations, Current Carrying Value
Available-for-Sale:
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Available-for-Sale, Less than 12 Months, Fair Value
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value
Available-for-sale, Less than 12 Months, Gross Unrealized Losses
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, 12 Months or More, Gross Unrealized Losses
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, Total Gross Unrealized Losses
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss
Held-to-Maturity:
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position [Abstract]
Held-to-Maturity, Less than 12 Months, Fair Value
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value
Held-to-Maturity, Less Than 12 Months, Gross Unrealized Losses
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss
Held-to-Maturity, 12 Months or More, Fair Value
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value
Held-to-Maturity, 12 Months or More, Gross Unrealized Losses
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss
Held-to-Maturity, Total Fair Value
Debt Securities, Held-to-maturity, Unrealized Loss Position, Fair Value
Held-to-Maturity, Total Gross Unrealized Losses
Debt Securities, Held-to-maturity, Unrealized Loss Position, Accumulated Loss
Investment securities in an unrealized loss position (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
Impairment loss
Other than Temporary Impairment Losses, Investments
Subsequent Events
Subsequent Events [Text Block]
Acquisitions
Mergers, Acquisitions and Dispositions Disclosures [Text Block]
Not Designated as Hedging Instrument
Interest rate swap contracts
Interest rate lock commitments
Interest Rate Lock Commitments [Member]
Forward loan sales contracts
Forward Contracts [Member]
Derivative Asset, Notional Amount
Derivative Asset, Notional Amount
Derivative Asset, Estimated Fair Value
Interest Rate Derivative Assets, at Fair Value
Derivative Liabilities, Estimated Fair Value
Interest Rate Derivative Liabilities, at Fair Value
Schedule of Allowance for Loan Losses by Portfolio Segment
Allowance for Credit Losses on Financing Receivables [Table Text Block]
Residential real estate
Real Estate Acquired Through Foreclosure, Acquired Through Acquisition
Real Estate Acquired Through Foreclosure, Acquired Through Acquisition
Real Estate Acquired Through Foreclosure, Acquired Through Acquisition
Real Estate Acquired Through Foreclosure [Roll Forward]
Real Estate Acquired Through Foreclosure [Roll Forward]
Real Estate Acquired Through Foreclosure [Roll Forward]
Beginning balance
Additions
Real Estate Acquired Through Foreclosure, Additions
Real Estate Acquired Through Foreclosure, Additions
Valuation adjustments
Real Estate Acquired Through Foreclosure, Valuation Adjustments
Real Estate Acquired Through Foreclosure, Valuation Adjustments
Dispositions
Real Estate Acquired Through Foreclosure, Disposals
Real Estate Acquired Through Foreclosure, Disposals
Ending balance
Consumer mortgage loans collateralized by residential real estate property in the process of foreclosure
Mortgage Loans in Process of Foreclosure, Amount
2018 remaining
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year
2018
Finite-Lived Intangible Assets, Amortization Expense, Year Two
2019
Finite-Lived Intangible Assets, Amortization Expense, Year Three
2020
Finite-Lived Intangible Assets, Amortization Expense, Year Four
2021
Finite-Lived Intangible Assets, Amortization Expense, Year Five
Thereafter
Finite-Lived Intangible Assets, Amortization Expense, after Year Five
Finite-Lived Intangible Assets, Net
Fair Value Measurements, Recurring and Nonrecurring [Table]
Fair Value Measurements, Recurring and Nonrecurring [Table]
Interest Rate Lock Commitments
Forward Contracts
Corporate securities
Fair Value Measured on a Recurring Basis
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets:
Derivative liabilities:
Long-lived assets to be disposed of by sale
Related allowance
Partial loan charge-offs
Impaired Financing Receivable, Related Allowance, Partial Loan Charge-Offs
Impaired Financing Receivable, Related Allowance, Partial Loan Charge-Offs
Statement of Comprehensive Income [Abstract]
Other comprehensive income, before tax:
Other Comprehensive Income (Loss), before Tax [Abstract]
Change in net unrealized (losses) gains during period
Change in unamortized loss on available-for-sale securities transferred into held-to-maturity
Defined benefit post-retirement benefits plans:
Defined Benefit Plan [Abstract]
Change in net actuarial gain
Deferred tax benefit (expense) related to other comprehensive income
Other comprehensive (loss) income, net of tax
Comprehensive income, net of tax
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Unrealized Gain (Loss) on Derivatives
Unrealized Gain (Loss) on Derivatives
Schedule of Financing Receivable, Allowance for Credit Losses [Table]
Schedule of Financing Receivable, Allowance for Credit Losses [Table]
Real Estate
Real Estate Portfolio Segment [Member]
Real Estate Portfolio Segment [Member]
Consumer
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
Provision charged to operating expense
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]
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
Allowance for loan losses
Loans held for investment:
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 Held For Investment, Evaluated for Impairment
Loans And Leases Receivable Held For Investment, Evaluated for Impairment
Allowance for credit losses due to subsequent impairment
Certain Loans and Debt Securities Acquired in Transfer, Allowance for Credit Losses Due to Subsequent Impairment
Revenue Recognition, Policy [Policy Text Block]
Revenue Recognition, Policy [Policy Text Block]
Derivative and Hedging Activities
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Commitments and Contingencies
Commitments and Contingencies Disclosure [Text Block]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]
Schedule of Acquired Loans not Deemed to Have Credit Impairment
Schedule of Acquired Loans not Deemed to Have Credit Impairment [Table Text Block]
Schedule of Acquired Loans not Deemed to Have Credit Impairment [Table Text Block]
Summary of Pro Forma Information
Business Acquisition, Pro Forma Information [Table Text Block]
Summary of Pre-tax Merger Related Expenses
Business Combination, Summary of Acquisition Costs [Table Text Block]
Business Combination, Summary of Acquisition Costs [Table Text Block]
Loans [Abstract]
Loans [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table]
Financing Receivable Portfolio Segment [Axis]
Financing Receivable Portfolio Segment [Axis]
Financing Receivable Portfolio Segment [Domain]
Financing Receivable Portfolio Segment [Domain]
Commercial Real Estate Construction [Member]
Collateral [Axis]
Collateral [Axis]
Collateral [Domain]
Collateral [Domain]
Geographic Distribution [Axis]
Geographic Distribution [Axis]
Geographic Distribution [Domain]
Geographic Distribution [Domain]
Class of Financing Receivable, Type of Borrower [Axis]
Class of Financing Receivable, Type of Borrower [Axis]
Class of Financing Receivable, Type of Borrower [Domain]
Class of Financing Receivable, Type of Borrower [Domain]
Industry of Counterparty, Type [Axis]
Industry of Counterparty, Type [Axis]
Industry of Counterparty [Domain]
Industry of Counterparty [Domain]
Legal Entity of Counterparty, Type [Axis]
Legal Entity of Counterparty, Type [Axis]
Legal Entity Type of Counterparty [Domain]
Legal Entity Type of Counterparty [Domain]
Counterparty Name [Axis]
Counterparty Name [Axis]
Counterparty Name [Domain]
Counterparty Name [Domain]
Subsegments [Axis]
Subsegments [Axis]
Subsegments [Domain]
Subsegments [Domain]
Geographical [Axis]
Geographical [Axis]
Geographical [Domain]
Geographical [Domain]
Billing Status, Type [Axis]
Billing Status, Type [Axis]
Receivables Billing Status [Domain]
Receivables Billing Status [Domain]
Receivable Type [Axis]
Receivable Type [Axis]
Receivable [Domain]
Receivable [Domain]
Industry Sector [Axis]
Industry Sector [Axis]
Industry Sector [Domain]
Industry Sector [Domain]
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Domain]
Concentration Risk Benchmark [Domain]
Concentration Risk Type [Axis]
Concentration Risk Type [Axis]
Concentration Risk Type [Domain]
Concentration Risk Type [Domain]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans And Leases Receivable Held For Investment
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage
Loans and Leases Receivable, Gross
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]
Unvested Restricted Stock
Restricted Stock [Member]
Restricted stock
Performance Shares [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]
Dilutive effects 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
Basic earnings per common share (in dollars per share)
Diluted earnings per common share (in dollars per share)
Anti-dilutive unvested time restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount
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
Capital Required for Capital Adequacy under Basel III Phase-in Schedule
Capital Required for Capital Adequacy under Basel III Phase-in Schedule
Capital Required for Capital Adequacy under Basel III Phase-in Schedule
Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets
Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets
Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets
Capital Required for Capital Adequacy under Basel III Fully Phased-in
Capital Required for Capital Adequacy under Basel III Fully Phased-in
Capital Required for Capital Adequacy under Basel III Fully Phased-in
Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets
Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets
Capital Required for Capital Adequacy under Basel III Fully Phased-in 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
Tier One Risk Based Capital under Basel III Phase-in Schedule
Tier One Risk Based Capital under Basel III Phase-in Schedule
Tier One Risk Based Capital under Basel III Phase-in Schedule
Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets
Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets
Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets
Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in 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
Common equity tier one risk-based capital:
Common equity tier one risk-based capital [Abstract]
Common equity tier one risk-based capital [Abstract]
Actual Amount
Common Equity Tier One Risked Based Capital
Common Equity Tier One Risked Based Capital
Actual Ratio
Common Equity Tier One Risk Based Capital to Risk Weighted Assets
Common Equity Tier One Risk Based Capital to Risk Weighted Assets
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Phase-in Schedule to Risk Weighted Assets
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in
Tier One Common Equity Capital Required for Capital Adequacy under Basel III Fully Phased-in
Tier One Common Equity Capital Required for Capital Adequacy under Basel III Fully Phased-in
Common Equity Tier One Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets
Tier One Common Equity Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets
Tier One Common Equity Capital Required for Capital Adequacy under Basel III Fully Phased-in to Risk Weighted Assets
Well Capitalized Amount
Common Equity Tier One Capital to be Well Capitalized
Common Equity Tier One Capital to be Well Capitalized
Well Capitalized Ratio
Common Equity Tier One Capital to be Well Capitalized to Risk Weighted Assets
Common Equity Tier One Capital 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
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]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]
Available-for-Sale Amortized Cost, Within One Year
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost
Available-for-Sale Amortized Cost, After One Year but Within Five Years
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost
Available-for-Sale Amortized Cost, After Five Years but Within Ten Years
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Amortized Cost
Available-for-Sale Amortized Cost, After Ten Years
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]
Available-for-Sale Estimated Fair Value, Within One Year
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value
Available-for-Sale Estimated Fair Value, After One Year but Within Five Years
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value
Available-for-Sale Estimated Fair Value, After Five Years but Within Ten Years
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value
Available-for-Sale Estimated Fair Value, After Ten Years
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value
Available-for-Sale, Estimated Fair Value
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount
Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract]
Held-to-Maturity Amortized Cost, Within One Year
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost
Held-to-Maturity Amortized Cost, After One Year but Within Five Years
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost
Held-to-Maturity Amortized Cost, After Five Years but Within Ten Years
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost
Held-to-Maturity Amortized Cost, After Ten Years
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, after 10 Years, Amortized Cost
Held-to-maturity Securities, Debt Maturities, Fair Value, Rolling Maturity
Debt Securities, Held-to-maturity, Maturity, Fair Value, Rolling Maturity [Abstract]
Held-to-Maturity Estimated Fair Value, Within One Year
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value
Held-to-Maturity Estimated Fair Value, After One Year but Within Five Years
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value
Held-to-Maturity Estimated Fair Value, After Five Years but Within Ten Years
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value
Held-to-Maturity Estimated Fair Value, After Ten Years
Debt Securities, Held-to-maturity, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value
Held-to-Maturity, Estimated Fair Value
Available-for-sale Securities and Held-to-maturity Securities
Debt Securities, Available-for-sale and Held-to-maturity [Abstract]
Amortized cost of investment securities callable 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
Fair value of investment securities callable 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
Business Combination, Acquisition Related Costs, Legal Fees
Business Combination, Acquisition Related Costs, Legal Fees
Business Combination, Acquisition Related Costs, Legal Fees
Business Combination, Acquisition Related Costs, Employee Expense
Business Combination, Acquisition Related Costs, Employee Expense
Business Combination, Acquisition Related Costs, Employee Expense
Business Combination, Acquisition Related Costs, Technology and Contract Termination
Business Combination, Acquisition Related Costs, Technology and Contract Termination
Business Combination, Acquisition Related Costs, Technology and Contract Termination
Business Combination, Acquisition Related Costs, Other Expenses
Business Combination, Acquisition Related Costs, Other Expenses
Business Combination, Acquisition Related Costs, Other Expenses