Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Stock-Based Compensation Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Deposits [Abstract] Interest bearing demand deposits Interest Expense, Demand Deposit Accounts Money market accounts Interest Expense, Money Market Deposits Savings accounts Interest Expense, Savings Deposits Certificate of deposit accounts Interest Expense Domestic Deposit Liabilities, Certificates of Deposit Total interest expense Interest Expense, Deposits Fair Value Disclosures [Abstract] Fair Value Inputs, Assets, Quantitative Information [Table] Fair Value Inputs, Assets, Quantitative Information [Table] Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Domain] Financial Instrument Performance Status [Domain] Impaired Loans Impaired Loans [Member] Impaired Loans [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 3 Fair Value, Inputs, Level 3 [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Nonrecurring Fair Value, Measurements, Nonrecurring [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Weighted Average Weighted Average [Member] Fair Value Inputs, Assets, Quantitative Information [Line Items] Fair Value Inputs, Assets, Quantitative Information [Line Items] Fair value measurements for financial instruments measured at fair value on a non-recurring basis Fair Value Inputs, Quantitative Information [Abstract] Fair Value Loans Receivable, Fair Value Disclosure Valuation Technique(s) Fair Value Measurements, Valuation Techniques Unobservable Input(s) Fair Value Measurements, Significant Assumptions Range of Inputs; Weighted Average Fair Value Inputs, Comparability Adjustments Stockholders' Equity Note [Abstract] Schedule of earnings per share reconciliation Schedule of Earnings Per Share Reconciliation [Abstract] Schedule of earnings per share reconciliation. Net income: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Net income Net Income (Loss) Attributable to Parent Less: Dividends and undistributed earnings allocated to participating securities Dividends and Undistributed Earnings Dividends and undistributed earnings. Net income allocated to common shareholders Undistributed Earnings, Diluted Basic: Weighted Average Number of Shares Outstanding, Basic [Abstract] Weighted average common shares outstanding (in shares) Gross Weighted Average Number of Shares Outstanding Basic Gross weighted average number of shares outstanding basic. Less: Restricted stock awards (in shares) Weighted Average Number of Shares, Restricted Stock Total basic weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic weighted average common shares outstanding (in shares) Incremental shares from stock options (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Total diluted weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Banking and Thrift [Abstract] Changes in other real estate owned Other Real Estate [Roll Forward] Balance at the beginning of the year Other Real Estate, Foreclosed Assets, and Repossessed Assets Additions Other Real Estate, Additions Proceeds from dispositions Other Real Estate, Disposals Gain (loss) on sales, net Gains (Losses) on Sales of Other Real Estate Valuation adjustment Other Real Estate, Valuation Adjustments Balance at the end of the year Income Tax Disclosure [Abstract] Deferred tax assets: Deferred Tax Assets, Gross [Abstract] Allowance for loan losses Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Provision for Loan Losses Accrued compensation Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Stock compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Net unrealized losses charged to other comprehensive income on securities Deferred Tax Assets, Unrealized Losses on Available-for-Sale Securities, Gross Market discount on purchased loans Deferred Tax Assets Market Discount on Loans Deferred Tax Assets Market Discount on Loans Foregone interest on nonaccrual loans Deferred Tax Assets, Foregone Interest on Nonaccrual Loans Deferred Tax Assets, Foregone Interest on Nonaccrual Loans Net operating loss carryforward acquired from NCB Deferred Tax Assets, Operating Loss Carryforwards Other deferred tax assets Deferred Tax Assets, Other Total deferred tax assets Deferred Tax Assets, Gross Deferred tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Deferred loan fees, net Deferred Tax Liabilities Deferred Loan Fees Deferred Tax Liabilities Deferred Loan Fees Premises and equipment Deferred Tax Liabilities, Property, Plant and Equipment FHLB stock Deferred Tax Liabilities, FHLB and FRB Stock Deferred Tax Liabilities, FHLB and FRB Stock Goodwill and other intangible assets Deferred Tax Liabilities, Goodwill and Intangible Assets Federal tax credits Deferred Tax Liabilities, Tax Credits Deferred Tax Liabilities, Tax Credits Junior subordinated debentures Deferred Tax Liabilities, Business Combination, Junior Subordinated Debentures Deferred Tax Liabilities, Business Combination, Junior Subordinated Debentures Other deferred tax liabilities Deferred Tax Liabilities, Other Total deferred tax liabilities Deferred Tax Liabilities, Gross Deferred tax asset, net Deferred Tax Assets, Net Receivables [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 business Commercial Portfolio Segment [Member] One-to-four family residential Residential Portfolio Segment [Member] Real estate construction and land development Real Estate Construction and Land Development [Member] Total real estate construction and land development. Consumer Consumer Portfolio Segment [Member] 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 and industrial Commercial and Industrial [Member] Commercial and industrial. Owner-occupied commercial real estate Owner Occupied Commercial Real Estate [Member] Owner occupied commercial real estate. Non-owner occupied commercial real estate Non Owner Occupied Commercial Real Estate [Member] Non owner occupied commercial real estate. One-to-four family residential One to Four Family Real Estate Construction [Member] One to Four Family Real Estate Construction [Member] Five or more family residential and commercial properties Five or More Family Residential and Commercial Properties [Member] Five or more family residential and commercial properties. Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Gross loans receivable Loans and Leases Receivable, Gross Net deferred loan costs Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums Loans receivable, net Loans and Leases Receivable, Net of Deferred Income Allowance for loan losses Loans and Leases Receivable, Allowance Total loans receivable, net Loans and Leases Receivable, Net Amount Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common stock Common Stock [Member] Retained earnings Retained Earnings [Member] Accumulated other comprehensive income (loss), net AOCI Attributable to Parent [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance, shares Shares, Outstanding Balance of AOCI at the beginning of the year Stockholders' Equity Attributable to Parent Restricted and unrestricted stock awards issued, net of forfeitures, shares Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Restricted and unrestricted stock awards granted, net of forfeitures Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Exercise of stock options (including net excess tax benefits/deficiencies from nonqualified options), shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercise of stock options (including excess tax benefits from nonqualified stock options) Stock Issued During Period, Value, Stock Options Exercised Restricted stock compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition Net excess tax benefits from vesting of restricted stock Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Common stock repurchased, shares Stock Repurchased and Retired During Period, Shares Common stock repurchased Stock Repurchased and Retired During Period, Value Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Cash dividends declared on common stock Dividends, Common Stock, Cash ASU 2018-02 Implementation Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings, Tax Effect Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings, Tax Effect Ending balance, shares Balance of AOCI at the end of the year Deposits Deposit Liabilities Disclosures [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Schedule of notional amounts and estimated fair values of interest rate derivative contracts Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Other Intangible Assets Goodwill Disclosure [Text Block] Debt Disclosure [Abstract] Schedule of FHLB advances Federal Home Loan Bank, Advances [Table Text Block] Commitments and Contingencies Disclosure [Abstract] Rental expense Operating Leases, Rent Expense, Net Quarterly Financial Information Disclosure [Abstract] Interest income Interest and Dividend Income, Operating 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 Noninterest income Noninterest Income Noninterest expense Noninterest Expense Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Basic earnings per common share (in usd per share) Earnings Per Share, Basic Diluted earnings per common share (in usd per share) Earnings Per Share, Diluted Cash dividends declared on common stock (in usd per share) Common Stock, Dividends, Per Share, Declared 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] Depreciation and amortization Depreciation, Amortization and Accretion, Net Changes in net deferred loan costs, net of amortization Amortization of Deferred Loan Origination Fees, Net Provision for loan losses Net change in accrued interest receivable, FDIC indemnification asset, prepaid expenses and other assets, and accrued expenses and other liabilities Net Change in Accrued Interest Receivable, Prepaid Expenses and Other Assets, Accrued Expenses and Other Liabilities Net change in accrued interest receivable, prepaid expenses and other assets, accrued expenses and other liabilities. Stock-based compensation expense Employee Benefits and Share-based Compensation Net excess tax benefit from exercise of stock-based compensation Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options and Restricted and Unrestricted Stock Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options and Restricted and Unrestricted Stock Amortization of intangible assets Amortization of Intangible Assets Origination of loans held for sale Payments for Origination and Purchases of Loans Held-for-sale Proceeds from sale of loans Proceeds from Sale of Loans Held-for-sale Earnings on bank owned life insurance Bank Owned Life Insurance Income Valuation adjustment on other real estate owned Gain on sale of loans, net Gain (Loss) on Sale of Loans and Leases Gain on sale of investment securities, net Gain (Loss) on Sale of Investments Gain on sale of assets held for sale Gain (Loss) of Assets Held for Sale Gain (Loss) of Assets Held for Sale (Gain) loss on sale of other real estate owned, net Gain on termination of FDIC shared-loss agreements Gain on termination of FDIC shared-loss agreements Gain on termination of FDIC shared-loss agreements Loss on sale or write-off of furniture, equipment and leasehold improvements Write off of leasehold improvements due to lease termination Write off of leasehold improvements due to lease termination 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] Loans originated, net of principal payments Payments for (Proceeds from) Loans and Leases Maturities of other interest earning deposits Proceeds from Sale and Maturity of Other Investments Maturities, calls and payments of investment securities available for sale Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Maturities, calls and payments of investment securities held to maturity Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities Purchase of investment securities available for sale Payments to Acquire Available-for-sale Securities Purchase of premises and equipment Payments to Acquire Property, Plant, and Equipment Purchase of other real estate owned Payments to Acquire Other Real Estate Proceeds from sales of other loans Proceeds from Sales of Assets, Investing Activities Proceeds from sales of other real estate owned Proceeds from Sale of Foreclosed Assets Proceeds from sales of investment securities available for sale Proceeds from Sale of Available-for-sale Securities Proceeds from sales of investment securities held to maturity Proceeds from Sale of Held-to-maturity Securities Proceeds from sales of assets held for sale Proceeds from Sale of Assets Held for Sale Proceeds from Sale of Assets Held for Sale Proceeds from redemption of FHLB stock Payments for (Proceeds from) Federal Home Loan Bank Stock Purchases of FHLB stock Payments to Acquire Federal Home Loan Bank Stock Proceeds from sales of premises and equipment Proceeds from Sale of Property, Plant, and Equipment Purchase of bank owned life insurance Purchase bank owned life insurance Purchase bank owned life insurance Proceeds from BOLI death benefit Proceeds from Life Insurance Policy Capital contributions to low-income housing tax credit partnerships and new market tax credit partnerships, net Change in low income tax housing tax credit partnership Change in low income tax housing tax credit partnership Net cash used for termination of FDIC shared-loss agreements Net cash used for termination of FDIC shared-loss agreements Net cash used for termination of FDIC shared-loss agreements 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 in deposits Increase (Decrease) in Deposits FHLB advances Increase (Decrease) in Loans to Federal Home Loan Banks Repayments of FHLB advances Repayments of Debt Common stock cash dividends paid Payments of Ordinary Dividends, Common Stock Net increase (decrease) in securities sold under agreement to repurchase Increase (Decrease) in Receivables under Repurchase Agreements Proceeds from exercise of stock options Proceeds from Stock Options Exercised Net excess tax benefit from exercise of stock-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Repurchase of common stock Payments for Repurchase of Common Stock Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Net (decrease) increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of year Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of year Supplemental disclosures of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid, Net Cash paid for income taxes Income Taxes Paid, Net Supplemental non-cash disclosures of cash flow information: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Transfers of loans receivable to other real estate owned Real Estate Owned, Transfer to Real Estate Owned Transfers of premises and equipment, net to prepaid expenses and other assets for properties held for sale Transfer of Property and Equipment to Prepaid Expenses and Other Assets Held-for-sale Transfer of Property and Equipment to Prepaid Expenses and Other Assets Held-for-sale Investment in low income housing tax credit partnership and related funding commitment Investment in low income housing tax partnership Investment in low income housing tax partnership Settlement of investment securities available for sale not settled at year end Purchase of investment securities available for sale not settled Purchase of investment securities available for sale not settled Transfer from investment securities held to maturity to available for sale Held-to-maturity Securities, Transferred to Available-for-sale Securities Held-to-maturity Securities, Transferred to Available-for-sale Securities Receivable due from bank owned life insurance contract Receivable Due from Bank Owned Life Insurance Contract Receivable Due from Bank Owned Life Insurance Contract Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [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] Carrying Value Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Schedule of carrying value and fair value of financial instruments Financial Instruments Financial Assets and Liabilities Balance Sheet Groupings [Abstract] Financial instruments financial assets and liabilities balance sheet groupings. Financial Assets: Assets [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Investment securities available for sale Available for Sale Securities Fair Value Available for sale securities fair value. Federal Home Loan Bank stock Investment in Federal Home Loan Bank Stock, Fair Value Disclosure Loans held for sale Loans Held-for-sale, Fair Value Disclosure Total loans receivable, net Accrued interest receivable Accounts Receivable, Fair Value Disclosure Derivative assets - interest rate swaps Derivative Assets - Interest Rate Swaps, Fair Value Disclosure Derivative Assets - Interest Rate Swaps, Fair Value Disclosure Financial Liabilities: Liabilities and Equity [Abstract] Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts Non Maturity Deposits Fair Value Disclosure Non maturity deposits fair value disclosure. Certificate of deposit accounts Certificate of Deposits Fair Value Disclosure Certificate of deposits fair value disclosure. Federal Home Loan Bank advances Federal Home Loan Bank Borrowings, Fair Value Disclosure Securities sold under agreement to repurchase Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure Junior subordinated debentures Junior Subordinated Debentures, Fair Value Disclosure Junior Subordinated Debentures, Fair Value Disclosure Accrued interest payable Accrued Liabilities, Fair Value Disclosure Derivative liabilities - interest rate swaps Derivative Liabilities - Interest Rate Swaps, Fair Value Disclosure Derivative Liabilities - Interest Rate Swaps, Fair Value Disclosure Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Credit facility with the FHLB Federal Home Loan Bank, Advances, General Debt Obligations, Maximum Amount Available Advances outstanding Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances FHLB Advances: Advances from Federal Home Loan Banks [Abstract] Average balance during the year Federal Home Loan Bank, Advances, Activity for Year, Average Balance of Agreements Outstanding Maximum month-end balance during the year Federal Home Loan Bank, Advances, Activity for Year, Maximum Outstanding at any Month End Weighted average rate during the year Federal Home Loan Bank, Advances, Activity for Year, Average Interest Rate for Year Weighted average rate at end of year Federal Home Loan Bank, Advances, Activity for Year, Average Interest Rate at Period End Federal Home Loan Bank, Advances [Table] Federal Home Loan Bank, Advances [Table] Federal Home Loan Bank, Advances [Line Items] Federal Home Loan Bank, Advances [Line Items] Unencumbered collateral in amount equal to varying percentages Unencumbered collateral in amount equal to varying percentages Unencumbered collateral in amount equal to varying percentages Retirement Benefits [Abstract] Employee Benefit Plans Compensation and Employee Benefit Plans [Text Block] 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] Financing Receivable, Recorded Investment [Line Items] Financing Receivable, Recorded Investment [Line Items] Pass Financing Receivables Pass Rated Financing receivables pass rated. OAEM Financing Receivables OAEM Rated Financing Receivables OAEM rated. Substandard Financing Receivables Substandard Rated Financing receivables substandard rated. Doubtful/Loss Financing Receivables Doubtful Rated Financing receivables doubtful rated. Total Potential problem loans receivable Potential Problem Loans Receivable Potential problem loans receivable. Government guaranteed potential problem loans Government Guaranteed Potential Problem Loans Government guaranteed potential problem loans. Regulatory Capital Requirements [Abstract] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Heritage Bank Heritage Bank [Member] Heritage bank. Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Common Equity Tier One Capital Required for Capital Adequacy Common Equity Tier One Capital Required for Capital Adequacy Common Equity Tier One Capital Required for Capital Adequacy to Average Assets Common Equity Tier One Capital Required for Capital Adequacy to Average Assets Common Equity Tier One Capital Required for Capital Adequacy to Average Assets Common Equity Tier One Capital Required to be Well-Capitalized Common Equity Tier One Capital Required to be Well-Capitalized Common Equity Tier One Capital Required to be Well Capitalized to Average Assets Common Equity Tier One Capital Required to be Well Capitalized to Average Assets Common Equity Tier One Capital Required to be Well Capitalized to Average Assets Common Equity Tier One Capital Common Equity Tier One Capital Common Equity Tier One Capital to Average Assets Common Equity Tier One Capital to Average Assets Common Equity Tier One Capital to Average Assets Tier One Leverage Capital Required for Capital Adequacy Tier One Leverage Capital Required for Capital Adequacy Tier One Leverage Capital Required for Capital Adequacy to Average Assets Tier One Leverage Capital Required for Capital Adequacy to Average Assets Tier One Leverage Capital Required to be Well Capitalized Tier One Leverage Capital Required to be Well Capitalized Tier One Leverage Capital Required to be Well Capitalized to Average Assets Tier One Leverage Capital Required to be Well Capitalized to Average Assets Tier One Leverage Capital Tier One Leverage Capital Tier One Leverage Capital to Average Assets Tier One Leverage Capital to Average Assets Tier One Risk Based Capital Required for Capital Adequacy Tier One Risk Based Capital Required for Capital Adequacy Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets Tier One Risk Based Capital Required to be Well Capitalized Tier One Risk Based Capital Required to be Well Capitalized Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets Tier One Risk Based Capital Tier One Risk Based Capital Tier One Risk Based Capital to Risk Weighted Assets Tier One Risk Based Capital to Risk Weighted Assets Capital Required for Capital Adequacy Capital Required for Capital Adequacy Capital Required for Capital Adequacy to Risk Weighted Assets Capital Required for Capital Adequacy to Risk Weighted Assets Capital Required to be Well Capitalized Capital Required to be Well Capitalized Capital Required to be Well Capitalized to Risk Weighted Assets Capital Required to be Well Capitalized to Risk Weighted Assets Capital Capital Capital to Risk Weighted Assets Capital to Risk Weighted Assets Capital conservation buffer, percentage Capital Conservation Buffer, Percentage Capital Conservation Buffer, Percentage Schedule of FDIC indemnification asset FDIC Indemnification Asset Roll Forward [Table Text Block] Condensed Financial Information of Parent Company Only Disclosure [Abstract] Condensed statements of financial condition Condensed Balance Sheet [Table Text Block] Condensed statements of income Condensed Income Statement [Table Text Block] Condensed statements of cash flows Condensed Cash Flow Statement [Table Text Block] 2018 Time Deposit Maturities, after Next Rolling Twelve Months 2019 Time Deposit Maturities, Rolling Year Two 2020 Time Deposit Maturities, Rolling Year Three 2021 Time Deposit Maturities, Rolling Year Four 2022 Time Deposit Maturities, Rolling Year Five Thereafter Time Deposit Maturities, after Rolling Year Five Certificates of deposit Interest-bearing Domestic Deposit, Certificates of Deposits Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Employee Stock Option Employee Stock Option [Member] Restricted Stock Awards Restricted Stock [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Option 1 Option One [Member] Option One. Option 2 Option Two [Member] Option two. the Plan Two Thousand Fourteen Omnibus Equity Plan [Member] Two Thousand Fourteen Omnibus Equity Plan [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Award 1 Share-based Compensation Award, Tranche One [Member] Award 2 Share-based Compensation Award, Tranche Two [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Expiration period Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Number of shares authorized for issuance Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized Shares remain available for future issuances under stock-based compensation plans Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Investments, Debt and Equity Securities [Abstract] Gross realized gains Available-for-sale Securities, Gross Realized Gains Gross realized losses Available-for-sale Securities, Gross Realized Losses Net realized gains Available-for-sale Securities, Gross Realized Gain (Loss) Minimum capital requirements to maintain leverage ratio Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block] Schedule of stock option activity Share-based Compensation, Activity [Table Text Block] Schedule of restricted stock award activity Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block] Schedule of assumptions of PRSUs granted Schedule of Share-based Payment Award, Equity Instruments Other than Options, Valuation Assumptions [Table Text Block] Schedule of Share-based Payment Award, Equity Instruments Other than Options, Valuation Assumptions [Table Text Block] Summary of RSU activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Future minimum lease payments Operating Leases, Future Minimum Payments Due FDIC Indemnification Asset FDIC Indemnification Asset Disclosure [Text Block] FDIC indemnification asset. FDIC Indemnification Asset [Roll Forward] FDIC Indemnification Asset [Roll Forward] Balance at the beginning of the year FDIC Indemnification Asset Cash payments received or receivable from the FDIC FDIC Indemnification Asset, Cash Payments Received FDIC share of additional estimated gains FDIC Indemnification Asset, Additional Estimated Losses Net amortization FDIC Indemnification Asset, Accretion of Discount Change due to termination of FDIC shared-loss agreements FDIC Indemnification Asset, Period Increase (Decrease) Balance at the end of the year Recurring Fair Value, Measurements, Recurring [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] U.S. Treasury and U.S. Government-sponsored agencies US Treasury and Government [Member] Municipal securities Municipal Bonds [Member] Residential mortgage-backed securities Residential Mortgage Backed Securities [Member] Commercial mortgage-backed securities Commercial Mortgage Backed Securities [Member] Collateralized loan obligations Collateralized Loan Obligations [Member] Corporate obligations Corporate Debt Securities [Member] Other securities Other Security Investments [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Assets Assets, Fair Value Disclosure [Abstract] Investment securities available for sale Available-for-sale Securities Derivative assets - interest rate swaps Derivative Asset, Fair Value, Gross Asset Liabilities Liabilities, Fair Value Disclosure [Abstract] Derivative liabilities - interest rate swaps Derivative Liability, Fair Value, Gross Liability Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Eleventh Plan Eleventh Stock Repurchase Plan [Member] [Member] Eleventh Stock Repurchase Plan [Member] [Member] Shares Related to Withholding Taxes on the Vesting of Restricted Stock Shares Related to Withholding Taxes on the Vesting of Restricted Stock [Member] Shares Related to Withholding Taxes on the Vesting of Restricted Stock [Member] Class of Stock [Line Items] Class of Stock [Line Items] Anti-dilutive securities excluded from computation (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Outstanding share percent Stock Repurchase Program Percentage of Outstanding Shares Authorized for Repurchase Stock repurchase program percentage of outstanding shares authorized for repurchase. Outstanding common shares in the plan Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Repurchased shares Stock Repurchased During Period, Shares Average price of shares repurchased (in usd per share) Treasury Stock Acquired, Average Cost Per Share Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Buildings and building improvements Building and Building Improvements [Member] Furniture, fixtures and equipment Furniture and Fixtures [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Useful lives Property, Plant and Equipment, Useful Life Heritage Financial Corporation (Parent Company Only) Condensed Financial Information of Parent Company Only Disclosure [Text Block] Number of FDIC-assisted acquisitions Number of FDIC-Assisted Acquisitions Number of FDIC-Assisted Acquisitions Consideration paid to FDIC for the termination of shared-loss agreements Consideration paid to FDIC for the termination of shared-loss agreements Consideration paid to FDIC for the termination of shared-loss agreements Gain on termination of FDIC shared-loss agreements FDIC indemnification asset FDIC clawback liability FDIC clawback liability FDIC clawback liability Finite-lived Intangible Assets [Roll Forward] Finite-lived Intangible Assets [Roll Forward] Balance at the beginning of the year Intangible Assets, Gross (Excluding Goodwill) Less: Amortization Balance at the end of the year Schedule of Deferred Compensation Arrangement with Individual, Postretirement Benefits [Table] Schedule of Deferred Compensation Arrangement with Individual, Postretirement Benefits [Table] 401(k) Plan and Trust Salary Saving Plan Heritage Financial Corporation 401(k) Plan and Trust Salary Saving Plan [Member] Heritage Financial Corporation 401(k) Plan and Trust Salary Saving Plan [Member] 401(k) Plan and Trust Heritage Financial Corporation 401(k) Plan and Trust [Member] Heritage Financial Corporation 401(k) Plan and Trust [Member] Deferred Compensation Plan deferred compensation plan [Member] deferred compensation plan [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Accrued expenses and other liabilities Accrued Expenses and Other Liabilities [Member] Accrued Expenses and Other Liabilities [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Washington Banking Washington Banking [Member] Washington Banking [Member] Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items] Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items] Minimum service days required for eligibility under the plan Minimum Service Days Required for Eligibility Under Plan Minimum Service Days Required for Eligibility Under Plan Employer matching contribution, percent of employee's gross pay Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Maximum annual contributions per employee, percent Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Percentage of employer contribution fully vested Percentage of Employer Contribution Fully Vested Percentage of Employer Contribution Fully Vested Defined contribution plan, employer matching contribution amount defined contribution plan, employer matching contribution amount defined contribution plan, employer matching contribution amount Minimum hours of service required for eligibility under the plan Minimum Hours of Service Required for Eligibility Under Plan Minimum Hours of Service Required for Eligibility Under Plan Minimum age required for eligibility under the plan Minimum Age Required for Eligibility Under Plan Minimum Age Required for Eligibility Under Plan Employer profit sharing contributions Defined Contribution Plan, Employer Contribution for Profit Sharing and Discretionary Defined Contribution Plan, Employer Contribution for Profit Sharing and Discretionary Compensation expense Deferred Compensation Arrangement with Individual, Compensation Expense Company's contributions Deferred Compensation Arrangement with Individual, Contributions by Employer Carrying value of obligation related to deferred compensation plan Deferred Compensation Arrangement with Individual, Recorded Liability Carrying value of obligation Liability for Future Policy Benefits, Life Dividends declared per common share (in usd per share) Changes in other real estate owned Other Real Estate, Roll Forward [Table Text Block] Loans held for sale Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage Loans and Leases Receivable Disclosure [Table] Loans and Leases Receivable Disclosure [Table] Loans and Leases Receivable Disclosure [Line Items] Loans and Leases Receivable Disclosure [Line Items] One-to-four family residential loans: Mortgage Banking [Abstract] Originated Payments for Origination of Mortgage Loans Held-for-sale Sold Proceeds from Sale of Mortgage Loans Held-for-sale Gains on sales of loans, net Gain (Loss) on Sale of Mortgage Loans Contractual amounts of commitments to sell and fund with off-balance sheet risk: Contractual Amounts of Commitments [Abstract] Contractual Amounts of Commitments [Abstract] Commitments to sell mortgage loans Loans and Leases Receivable, Commitments to Purchase or Sell Commitments to fund mortgage loans (at interest rates approximating market rates) for portfolio or for sale: Commitments to Fund Mortgage Loans [Abstract] Commitments to Fund Mortgage Loans [Abstract] Fixed rate Loans and Leases Receivable, Commitments, Fixed Rates Variable or adjustable rate Loans and Leases Receivable, Commitments, Variable Rates Total commitments to fund mortgage loans Loans and Leases Receivable, Total Commitments to Purchase or Sell Loans and Leases Receivable, Total Commitments to Purchase or Sell Percentage of losses absorbed by FDIC Percentage of Losses Absorb by Federal Deposit Insurance Corporation Percentage of Losses Absorb by Federal Deposit Insurance Corporation Percentage of loss recoveries received by FDIC Percentage of Loss Recoveries Received by FDIC Percentage of Loss Recoveries Received by FDIC Document and Entity Information [Abstract] Document and entity information. Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Public Float Entity Public Float Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Unallocated Unallocated [Member] Unallocated. Schedule of allowance for loan losses on the basis of impairment method Allowance for Loan and Lease Losses [Roll Forward] Balance at the beginning of the year Charge-offs Allowance for Loan and Lease Losses, Write-offs Recoveries Allowance for Loan and Lease Loss, Recovery of Bad Debts Balance at the end of the year 2018 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Intangible assets, net Finite-Lived Intangible Assets, Net Results of operations on a quarterly basis Quarterly Financial Information [Table Text Block] Equity [Abstract] Changes in fair value of available for sale securities Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Accretion of other-than- temporary impairment on held to maturity securities Accretion of Other-than-Temporary-Impairment on Held to Maturity Securities [Member] Accretion of Other-than-Temporary-Impairment on Held to Maturity Securities [Member] AOCI attributable to parent Other comprehensive income (loss) before reclassification (1) Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassified from AOCI for gain on sale of investment securities included in net income (1) Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Transfer of investment securities from held to maturity to available for sale, net of tax of $0, $0 and $334, respectively Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax Other comprehensive income (loss) Line of Credit Facility [Table] Line of Credit Facility [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Federal Reserve Bank Advances Federal Reserve Bank Advances [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Borrowings outstanding Line of Credit Facility Line of Credit Facility Allowance for off-balance sheet financial instruments Allowance for Loan losses for Off Balance Sheet Financial Instruments Allowance for Loan losses for Off Balance Sheet Financial Instruments Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Schedule of Financing Receivable, Troubled Debt Restructurings [Table] Nonaccrual Nonaccrual [Member] nonaccrual [Member] Restructured performing Restructured Performing [Member] Restructured Performing [Member] Financing Receivable, Modifications [Line Items] Financing Receivable, Modifications [Line Items] Average recorded investment of impaired loans Impaired Financing Receivable, Average Recorded Investment Interest income recognized Impaired Financing Receivable, Interest Income, Accrual Method Disclosure of Repurchase Agreements [Abstract] Repurchase agreement obligation by class of collateral pledged Schedule of Repurchase Agreements [Table Text Block] Investment Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Debt Security [Axis] Debt Security [Axis] Major Types of Debt Securities [Domain] Major Types of Debt Securities [Domain] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Amortized Cost Available-for-sale Securities, Amortized Cost Basis Gross Unrealized Gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Fair Value Change in other intangible assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Estimated aggregate amortization expense for future years Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Income Taxes Income Tax Disclosure [Text Block] Peer Company Peer Company [Member] Peer Company [Member] PRSU Performance-Based Restricted Stock Units (PRSUs) [Member] Performance-based Restricted Stock Units (PRSUs) [Member] Shares issued Stock Issued During Period, Shares, Share-based Compensation, Gross Expected Term in Years Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Weighted-Average Risk Free Interest Rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected Dividend Yield (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Weighted-Average Fair Value (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Volatility Rate, Minimum Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum Volatility Rate, Maximum Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum Correlation Coefficient Rate Share-Based Compensation Arrangement By Share-Based Payment Award, Correlation Coefficient Rate Share-Based Compensation Arrangement By Share-Based Payment Award, Correlation Coefficient Rate Volatility Rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Amount Deposits Liabilities, Balance Sheet, Reported Amounts [Abstract] Noninterest demand deposits Noninterest-bearing Domestic Deposit, Demand Interest bearing demand deposits Interest-bearing Domestic Deposit, Demand Money market accounts Interest-bearing Domestic Deposit, Money Market Savings accounts Interest-bearing Domestic Deposit, Savings Total non-maturity deposits Interest-bearing Domestic Deposit, Time Deposits Certificate of deposit accounts Total deposits Deposits Percent Percentage of Interest-bearing Domestic Deposit Liabilities to Deposit Liabilities [Abstract] Noninterest demand deposits (as a percent) Percentage Of Noninterest-Bearing Domestic Deposit, Demand Percentage Of Noninterest-Bearing Domestic Deposit, Demand Interest bearing demand deposits (as a percent) Percentage of Interest-bearing Domestic Deposits to Deposits, Demand Money market accounts (as a percent) Percentage of Interest-bearing Domestic Deposits to Deposits, Money Market Savings accounts (as a percent) Percentage of Interest-bearing Domestic Deposits to Deposits, Savings Total non-maturity deposits (as a percent) Percentage of Interest-bearing Domestic Deposits to Deposits, Time Deposits Certificate of deposit accounts (as a percent) Percentage of Interest-bearing Domestic Deposits to Deposits, Certificates of Deposit Total deposits (as a percent) Percentage of Interest-bearing Domestic Deposits to Deposits Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Concentration of loans greater than 10% Concentration Risk Percentage Greater than Ten Percent Concentration risk percentage greater than ten percent. Percentage of concentrations of loans in any industry (in excess of 10%) (percent) Concentration Risk, Percentage Schedule of changes in allowance for loan losses Allowance for Credit Losses on Financing Receivables [Table Text Block] Schedule of loan receivables on the basis of impairment method Schedule of Financing Receivables for Credit Losses [Table Text Block] Schedule detailing information related to financing receivables by portfolio segment. A portfolio segment is a level at which an entity develops and documents a systematic methodology to determine its allowance for credit losses. Reconciliation of available for sale securities Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Schedule of securities available for sale Available-for-sale Securities [Table Text Block] Schedule of fair value and unrealized losses of available for sale investment securities Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block] Gross realized gains and losses on sale of securities available for sale Schedule of Realized Gain (Loss) [Table Text Block] Scheduled of amortized cost and fair value of securities pledged as collateral Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block] Loans and Leases Receivable Disclosure [Abstract] Schedule of loans receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Loans receivable by credit quality indicator Financing Receivable Credit Quality Indicators [Table Text Block] Schedule of nonaccrual loans Schedule of Financing Receivables, Non Accrual Status [Table Text Block] Past due financing receivables Past Due Financing Receivables [Table Text Block] Schedule of impaired loans, including restructured Impaired Financing Receivables [Table Text Block] Schedule of average recorded investment impaired loans including restructuring loans Schedule of Average Recorded Investment Impaired Loans Including Restructuring Loans [Table Text Block] Schedule of average recorded investment impaired loans including restructuring loans. Recorded investment balance and related allowance for loan losses of accruing and non-accruing TDRs Troubled Debt Restructurings of Financing Receivables on Basis of Accruing and Non Accruing [Table Text Block] Troubled debt restructurings of financing receivables on basis of accruing and non accruing. Troubled debt restructurings on financing receivables Troubled Debt Restructurings on Financing Receivables [Table Text Block] Troubled debt restructuring loans, subsequently defaulted Troubled Debt Restructurings Loans Subsequently Defaulted [Table Text Block] Troubled debt restructurings loans subsequently defaulted. Purchased impaired loans Schedule of Financing Receivables Loans Acquired with Credit Deterioration [Table Text Block] Schedule of financing receivables loans acquired with credit deterioration. Schedule of impaired purchased loans accretable yield Schedule of Impaired Purchased Loans Accretable Yield [Table Text Block] Schedule of impaired purchased loans accretable yield. Activity in related party loans Schedule of Related Party Transactions [Table Text Block] Mortgage banking activities Loans and Leases Receivable, Mortgage Banking Activities [Table Text Block] Loans and Leases Receivable, Mortgage Banking Activities [Table Text Block] Contractual amounts of commitments to sell and fund with off-balance sheet risk Contractual Amounts of Commitments with Off-balance Sheet Risk [Table Text Block] Contractual Amounts of Commitments with Off-balance Sheet Risk [Table Text Block] Details of SBNA loans serviced Summary of Servicing of Financial Assets [Table Text Block] Summary of Servicing of Financial Assets [Table Text Block] Securities classified as trading Trading Securities Securities classified as held to maturity Held-to-maturity Securities OTTI, unrealized losses Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Held-to-maturity Securities Description of Business Description of Business [Policy Text Block] The entire disclosure for the business description and basis of presentation concepts. Business description describes the nature and type of organization including but not limited to organizational structure as may be applicable to holding companies, parent and subsidiary relationships, business divisions, business units, business segments, affiliates and information about significant ownership of the reporting entity. Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Reclassifications Reclassification, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Investment Securities Marketable Securities, Policy [Policy Text Block] Loans Held for Sale Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block] Loans Receivable and Loan Commitments Loans Receivable and Loan Commitments Policy [Policy Text Block] Loans Receivable and Loan Commitments Policy [Policy Text Block] Loan Fees and Costs Deferred Charges, Policy [Policy Text Block] Allowance for Loan Losses Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block] Mortgage Banking Operations Loans and Leases Receivable, Mortgage Banking Activities, Policy [Policy Text Block] FDIC Indemnification Asset FDIC Indemnification Asset Policy [Policy Text Block] FDIC Indemnification Asset Policy [Policy Text Block] Other Real Estate Owned Real Estate, Policy [Policy Text Block] Premises and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Bank Owned Life Insurance Life Insurance, Corporate or Bank Owned Policy [Policy Text Block] Life Insurance, Corporate or Bank Owned Policy [Policy Text Block] Other Intangible Assets Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block] Goodwill Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Stock-Based Compensation and Deferred Compensation Plan Compensation Related Costs, Policy [Policy Text Block] Earnings per Share Earnings Per Share, Policy [Policy Text Block] Derivative Financial Instruments Derivatives, Policy [Policy Text Block] Operating Segments Segment Reporting, Policy [Policy Text Block] Recently Issued Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] RSU Restricted Stock Units (RSUs) [Member] Performance period Actual payout percentage Share-Based Compensation Arrangement By Share-Based Payment Award, Actual Payout Percentage Share-Based Compensation Arrangement By Share-Based Payment Award, Actual Payout Percentage Compensation expense Allocated Share-based Compensation Expense Tax benefit Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Total unrecognized compensation expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Weighted average, recognition period Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Schedule of restricted stock award activity Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Nonvested at beginning of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Nonvested at end of period (in shares) Weighted-Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Nonvested at beginning of period (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in usd per share) Vested (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Nonvested at end of period (in usd per share) Statement of Financial Position [Abstract] Preferred stock, par value (in usd per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Common stock, par value (in usd per share) Common Stock, No Par Value Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Common Stock, Shares, Outstanding Schedule of Impaired Financing Receivable [Table] Schedule of Impaired Financing Receivable [Table] Financing Receivable, Impaired [Line Items] Financing Receivable, Impaired [Line Items] Outstanding Principal Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance Recorded Investment Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount The recorded balance after any applicable reductions (i.e. outstanding balance net of unamortized accretable yield). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable. Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Loans and Leases Receivable, Related Parties [Roll Forward] Loans and Leases Receivable, Related Parties [Roll Forward] Balance outstanding at beginning of year Loans and Leases Receivable, Related Parties Principal additions Loans and Leases Receivable, Related Parties, Additions Elimination of outstanding loan balance due to change in related party status Loans and Leases Receivable, Related Parties, Elimination Due to Change in Related Party Status Loans and Leases Receivable, Related Parties, Elimination Due to Change in Related Party Status Principal reductions Loans and Leases Receivable, Related Parties, Proceeds Balance outstanding at end of year Unfunded commitments to related parties Unfunded Commitments on Loans and Leases Receivable Related Parties Unfunded Commitments on Loans and Leases Receivable Related Parties Property, Plant and Equipment [Abstract] Schedule of premises and equipment Property, Plant and Equipment [Table Text Block] 2018 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2019 Operating Leases, Future Minimum Payments, Due in Two Years 2020 Operating Leases, Future Minimum Payments, Due in Three Years 2021 Operating Leases, Future Minimum Payments, Due in Four Years 2022 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Future minimum annual rental commitments Mortgage Loans on Real Estate Schedule [Table] Mortgage Loans on Real Estate Schedule [Table] Mortgage Loans on Real Estate [Line Items] Mortgage Loans on Real Estate [Line Items] Carrying amount of other real estate owned from foreclosure Mortgage loans secured by residential real estate properties Mortgage Loans in Process of Foreclosure, Amount Schedule of deposits Schedule of Interest Bearing Deposit Liabilities Domestic by Component [Table Text Block] Schedule of interest bearing deposit liabilities domestic by component. Schedule of interest expense, by category Schedule of Interest Expense Deposits [Table Text Block] Schedule of interest expense deposits. Schedule of maturities of certificates of deposit Schedule of Maturities of Time Deposits [Table Text Block] Schedule of maturities of time deposits. Condensed Balance Sheet Statement [Table] Condensed Balance Sheet Statement [Table] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Parent Company Parent Company [Member] Condensed Balance Sheet Statements, Captions [Line Items] Condensed Balance Sheet Statements, Captions [Line Items] ASSETS Cash and interest earning deposits Cash Equivalents, at Carrying Value Investment in subsidiary bank Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Other assets Other Assets Total assets Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Junior subordinated debentures Junior Subordinated Notes Other liabilities Other Liabilities Total stockholders’ equity Total liabilities and stockholders’ equity Liabilities and Equity Gross nonaccrual loans Financing Receivable, Recorded Investment, Nonaccrual Status Nonaccrual originated loans guaranteed by governmental agencies Government Guarantee of Non Accrual Loans Government Guarantee of Non Accrual Loans 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] 30-89 Days Financing Receivables, 30 to 89 Days Past Due [Member] Financing Receivables, 30 to 89 Days Past Due [Member] 90 Days or Greater Financing Receivables, Equal to Greater than 90 Days Past Due [Member] Financing Receivable, Recorded Investment, Past Due [Line Items] Financing Receivable, Recorded Investment, Past Due [Line Items] Total Past Due Financing Receivable, Recorded Investment, Past Due Current Financing Receivable, Recorded Investment, Current 90 Days or More and Still Accruing Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing Accrued interest payable on deposits Deposit Liabilities, Accrued Interest Certificates of deposit equal to or in excess of $250,000 Time Deposits, $250,000 or More, Domestic Time Deposits, $250,000 or More, Domestic Restricted stock awards issued, net of forfeitures Stock Issued During Period, Value, Restricted Stock Award, Gross PCI Loans Purchase Credit Impaired Loans [Member] [Domain] Purchase Credit Impaired Loans [Member] [Domain] Certain Loans Acquired in Transfer Not Accounted for as 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] Balance at the beginning of the year Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Accretion Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion Disposal and other Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Disposals of Loans Change in accretable yield Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications (to) from Nonaccretable Difference Balance at the end of the year Bank owned life insurance Bank Owned Life Insurance Loan Receivable Financing Receivables [Text Block] ASSETS Cash on hand and in banks Cash and Due from Banks Interest earning deposits Interest-bearing Deposits in Banks and Other Financial Institutions Cash and cash equivalents Investment securities available for sale, at fair value Loans receivable, net Other real estate owned Premises and equipment, net Property, Plant and Equipment, Net Federal Home Loan Bank stock, at cost Federal Home Loan Bank Stock Accrued interest receivable Interest Receivable Prepaid expenses and other assets Prepaid Expense and Other Assets Other intangible assets, net Intangible Assets, Net (Excluding Goodwill) Goodwill Goodwill LIABILITIES AND STOCKHOLDERS' EQUITY Deposits Federal Home Loan Bank advances Long-term Federal Home Loan Bank Advances Junior subordinated debentures Securities sold under agreement to repurchase Securities Sold under Agreements to Repurchase Accrued expenses and other liabilities Total liabilities Liabilities Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, no par value, 2,500,000 shares authorized; no shares issued and outstanding at December 31, 2017 and 2016 Preferred Stock, Value, Issued Common stock, no par value, 50,000,000 shares authorized; 29,927,746 and 29,954,931 shares issued and outstanding at December 31, 2017 and 2016, respectively Common Stock, Value, Issued Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss, net Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Condensed Income Statement [Table] Condensed Income Statement [Table] Condensed Income Statements, Captions [Line Items] Condensed Income Statements, Captions [Line Items] Interest and dividends on interest earning deposits and other assets Interest Income, Deposits with Financial Institutions Total interest income Junior subordinated debentures Interest Expense, Junior Subordinated Debentures Total interest expense Dividends from subsidiary bank Dividend Income, Operating Equity in undistributed income of subsidiary bank Equity in Undistributed Income of Subsidiaries Equity in Undistributed Income of Subsidiaries Total noninterest income Professional services Professional Fees Other expense Other Noninterest Expense Total noninterest expense Income tax expense Employee Stock Option [Member] Intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Troubled Debt Restructured Loans Troubled Debt Restructured Loans [Member] Troubled debt restructured loans. Number of Contracts Financing Receivable, Modifications, Number of Contracts Outstanding Principal Balance Financing Receivable, Modifications, Post-Modification Recorded Investment Initial advance at the time of modification Loans and Leases Receivable, Impaired, Initial Loan DIsbursement Loans and Leases Receivable, Impaired by Modification, Initial Loan Disbursement on construction-type loans. Number of loan segments Number of Loan Segments Number of loan segments. Maximum percent of appraised value or underlying collateral mortgage (not to exceed 80%) residential loans (percent) Maximum Loans and Leases Receivable Percent of Appraised Value or Underlying Collateral Mortgage Residential Loans Maximum loans and leases receivable percent of appraised value or underlying collateral mortgage residential loans. Loan term Loans and Leases Receivable, maturity Term Loans and leases receivable, maturity term. Maximum percentage consumer loans (percent) Loans and Leases Receivable Maximum Percentage Consumer Loans Loans and leases receivable maximum percentage consumer loans. Stock option activity Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward] Outstanding at beginning of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Exercised (in shares) Forfeited or expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Outstanding at end of period (in shares) Vested and expected to vest at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Exercisable at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted-Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Outstanding at beginning of period (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Exercised (in usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Forfeited or expired (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Outstanding at end of period (in usd per share) Vested and expected to vest at end of period (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Exercisable at end of period (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted-Average Remaining Contractual Term, Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted-Average Remaining Contractual Term, Vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Weighted-Average Remaining Contractual Term, Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Aggregate Intrinsic Value, Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Aggregate Intrinsic Value, Vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Aggregate Intrinsic Value, Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent event Subsequent Event [Member] Puget Sound Merger Puget Sound Bancorp, Inc. [Member] Puget Sound Bancorp, Inc. [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Business and occupation tax audit Business and Occupation Tax Audit [Member] Business and Occupation Tax Audit [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Number of Heritage common stock for each share of Puget Sound stock (in shares) Business Combination, Consideration Transferred, Equity Interests Issued And Issuable, Entity Shares Issued Per Acquiree Share Business Combination, Consideration Transferred, Equity Interests Issued And Issuable, Entity Shares Issued Per Acquiree Share Number of shares issued Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Closing date price (in usd per share) Business Acquisition, Share Price Total consideration paid Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Total amount of preliminary findings with back interest Loss Contingency, Preliminary Findings Loss Contingency, Preliminary Findings Number of Contracts Financing Receivable, Modifications, Subsequent Default, Number of Contracts Outstanding Principal Balance Financing Receivable, Modifications, Subsequent Default, Recorded Investment Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Current tax expense Current Income Tax Expense (Benefit) Deferred tax expense Deferred Income Tax Expense (Benefit) Income tax expense Investment Holdings [Table] Investment Holdings [Table] Investment Holdings [Line Items] Investment Holdings [Line Items] Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Less than 12 Months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value 12 Months or Longer Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Total