Allowance for Credit Losses on Loans - Summary of Changes in Loan Allowance (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	$ 52,529	$ 51,219	$ 52,468	$ 47,999
Charge-offs	374	2,645	1,308	3,395
Recoveries	256	112	397	908
Provision for (Reversal of) Credit Losses	(1,563)	(2,705)	(2,417)	(5,879)
Ending Balance	53,974	51,391	53,974	51,391
Schedule of Changes in Allowance For Credit Losses on Unfunded Commitments [Line Items]
Beginning Balance	740	774	587	1,288
Provision for (reversal of) credit losses on unfunded commitments	212	(266)	365	(780)
Ending Balance	952	508	952	508
Commercial Business
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	38,353	34,467	38,293	31,303
Charge-offs	195	2,560	871	2,949
Recoveries	219	72	263	807
Provision for (Reversal of) Credit Losses	31	(5,188)	(661)	(8,006)
Ending Balance	38,346	37,167	38,346	37,167
Commercial Business \| Commercial and industrial
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	9,385	11,134	9,766	11,128
Charge-offs	195	50	871	439
Recoveries	78	72	122	448
Provision for (Reversal of) Credit Losses	17	472	(234)	453
Ending Balance	9,251	10,684	9,251	10,684
Commercial Business \| Owner Occupied Commercial Real Estate [Member]
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	13,434	9,850	12,819	8,999
Charge-offs	0	2,510	0	2,510
Recoveries	141	0	141	359
Provision for (Reversal of) Credit Losses	373	(4,819)	(242)	(5,311)
Ending Balance	13,202	12,159	13,202	12,159
Commercial Business \| Non-owner-occupied CRE
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	15,534	13,483	15,708	11,176
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for (Reversal of) Credit Losses	(359)	(841)	(185)	(3,148)
Ending Balance	15,893	14,324	15,893	14,324
Residential Portfolio Segment [Member]
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	3,942	3,735	3,464	3,473
Charge-offs	27	0	27	0
Recoveries	1	0	1	0
Provision for (Reversal of) Credit Losses	(167)	131	(645)	(131)
Ending Balance	4,083	3,604	4,083	3,604
Real estate construction and land development:
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	8,316	10,818	8,656	10,876
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for (Reversal of) Credit Losses	(1,340)	2,353	(1,000)	2,411
Ending Balance	9,656	8,465	9,656	8,465
Real estate construction and land development: \| Real estate construction and land development:
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	868	910	779	1,643
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for (Reversal of) Credit Losses	(140)	118	(229)	851
Ending Balance	1,008	792	1,008	792
Real estate construction and land development: \| Commercial and multifamily
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	7,448	9,908	7,877	9,233
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for (Reversal of) Credit Losses	(1,200)	2,235	(771)	1,560
Ending Balance	8,648	7,673	8,648	7,673
Consumer
Schedule of Changes in Allowance For Credit Losses on Loans Receivable [Line Items]
Beginning Balance	1,918	2,199	2,055	2,347
Charge-offs	152	85	410	446
Recoveries	36	40	133	101
Provision for (Reversal of) Credit Losses	(87)	(1)	(111)	(153)
Ending Balance	$ 1,889	$ 2,155	$ 1,889	$ 2,155

HERITAGE FINANCIAL CORP /WA/ 10-Q