XML 45 R1.htm IDEA: XBRL DOCUMENT v3.20.2
Cover Page Cover Page
 3 Months Ended
Oct. 22, 2020
Jul. 23, 2020
Sep. 30, 2020
Document Information [Line Items]      
Document Type 8-K    
Document Period End Date Oct. 22, 2020    
Entity Registrant Name HERITAGE FINANCIAL CORP    
Entity File Number   000-29480  
Entity Incorporation, State or Country Code WA    
Entity Tax Identification Number 91-1857900    
Entity Address, Address Line One 201 Fifth Avenue SW,    
Entity Address, City or Town Olympia    
Entity Address, State or Province WA    
Entity Address, Postal Zip Code 98501    
City Area Code (360)    
Local Phone Number 943-1500    
Written Communications false    
Soliciting Material false    
Pre-commencement Tender Offer false    
Pre-commencement Issuer Tender Offer false    
Title of 12(b) Security Common stock, no par value    
Trading Symbol HFWA    
Security Exchange Name NASDAQ    
Entity Emerging Growth Company false    
Entity Central Index Key     0001046025
Amendment Flag false