Description of Business, Basis of Presentation and Significant Accounting Policies and Recently Issued Accounting Pronouncements	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business, Basis of Presentation and Significant Accounting Policies and Recently Issued Accounting Pronouncements	Description of Business, Basis of Presentation, Significant Accounting Policies and Recently Issued Accounting Pronouncements (a) Description of Business The Company is primarily engaged in the business of planning, directing and coordinating the business activities of its wholly-owned subsidiary, Heritage Bank. The Bank is headquartered in Olympia, Washington and conducts business from its 53 branch offices as of June 30, 2021 located throughout Washington State and the greater Portland, Oregon area. The Bank’s business consists primarily of commercial lending and deposit relationships with small and medium-sized businesses and their owners in its market areas and attracting deposits from the general public. The Bank also makes real estate construction and land development loans, consumer loans and originates first mortgage loans on residential properties primarily located in its market areas. The Bank's deposits are insured by the FDIC. The Company announced a plan in July 2021 to consolidate four branches during October 2021 to create a more efficient branch footprint. This will reduce the branch count from 53 to 49. The Company plans to integrate these locations into other branches within its network. (b) Basis of Presentation The accompanying unaudited Condensed Consolidated Financial Statements have been prepared in accordance with GAAP for interim financial information and pursuant to the rules and regulations of the SEC. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. It is recommended that these unaudited Condensed Consolidated Financial Statements and accompanying Notes be read with the audited Consolidated Financial Statements and the accompanying Notes included in the 2020 Annual Form 10-K. In management's opinion, all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the six months ended June 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. To prepare unaudited Condensed Consolidated Financial Statements in conformity with GAAP, management makes estimates and assumptions based on available information. These estimates and assumptions affect the amounts reported in the financial statements and the disclosures provided. Management believes that the judgments, estimates, and assumptions used in the preparation of the Condensed Consolidated Financial Statements are appropriate based on the facts and circumstances at the time. Actual results, however, could differ significantly from those estimates. Material estimates that are particularly susceptible to significant change relate to management's estimate of ACL on loans, management's estimate of ACL on unfunded commitments, management's evaluation of goodwill impairment and management's estimate of the fair value of financial instruments. The accompanying Condensed Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiary, the Bank. All significant intercompany balances and transactions among the Company and the Bank have been eliminated in consolidation. Certain prior year amounts in the Condensed Consolidated Statements of Income and the Condensed Consolidated Statements of Cash Flows have been reclassified to conform to the current year’s presentation. Reclassifications had no effect on the prior years' net income or stockholders’ equity. (c) Significant Accounting Policies The significant accounting policies used in preparation of the Condensed Consolidated Financial Statements are disclosed in greater detail in the 2020 Annual Form 10-K. There have not been any material changes in the Company's significant accounting policies from those contained in the 2020 Annual Form 10-K during the six months ended June 30, 2021. (d) Recently Issued or Adopted Accounting Pronouncements FASB ASU 2016-13, Financial Instruments: Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, as amended by ASU 2018-19, ASU 2019-04, ASU 2019-05, ASU 2019-10, ASU 2019-11, and ASU 2020-02, was originally issued in June 2016. This ASU replaced the incurred loss methodology with an expected loss methodology, which is commonly referred to as the "CECL" methodology. The measurement of expected credit losses under the CECL methodology is applicable to financial assets measured at amortized cost, including loans receivable. It also applies to off-balance sheet credit exposures such as loan commitments, standby letters of credit, financial guarantees, and other similar instruments. In addition, CECL Adoption made changes to the accounting for credit losses on investment securities available for sale. This ASU requires financial assets measured at amortized cost basis to be presented at the net amount expected to be collected. For public business entities, this ASU is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years with early adoption permitted for fiscal years after December 15, 2018 and can be delayed under a provision of the CARES Act until the end of the official health emergency declaration. The Bank adopted ASU 2016-13 on January 1, 2020 using the modified retrospective method for all financial assets measured at amortized cost and unfunded commitments. At adoption, the Bank elected not to measure an ACL on accrued interest receivable on loans receivable or accrued interest receivable on investment securities available for sale as Bank policy is to reverse interest income for uncollectible accrued interest receivable balances in a timely manner. The adoption of ASU 2016-13 included an increase to the ACL on loans of $3.4 million and an increase to the ACL on unfunded commitments of $3.7 million, resulting in a pretax cumulative-effect adjustment of $7.1 million. The impact of this adjustment to beginning retained earnings on January 1, 2020 was $5.6 million, net of tax. FASB ASU 2020-04, Reference Rate Reform (Topic 848), as amended by ASU 2021-01, was issued in March 2020 and provides optional guidance for a limited period of time to ease the potential burden in accounting for (or recognizing the effects of) reference rate reform on financial reporting. The amendments in this ASU are effective for all entities as of March 12, 2020 through December 31, 2022. The amendments are elective, apply to all entities, and provide optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The Bank’s swap-related transactions are the majority of the Company's LIBOR exposure. Effective January 25, 2021, the Company adhered to the Interbank Offered Rate Fallbacks Protocol as published by the International Swaps and Derivatives Association, Inc. and recommended by the Alternative Reference Rates Committee. The Company does not expect this ASU to have a material impact on its business operations and the Condensed Consolidated Financial Statements.