Loans - Net Loans Held-for-Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Jun. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Loans and Leases Receivable Disclosure [Line Items]
Total loans held-for-investment	$ 3,900,346		$ 4,022,224
Allowance for credit losses	(36,890)	$ (36,120)	(35,183)	$ (35,197)	$ (34,780)	$ (37,535)
Net loans held-for-investment	3,863,456		3,987,041
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Loans and Leases Receivable Disclosure [Line Items]
Total loans held-for-investment	3,891,928		4,013,051
Allowance for credit losses	(34,237)	(33,403)	(32,279)	(32,273)	(31,835)	(34,450)
PCD loans
Loans and Leases Receivable Disclosure [Line Items]
Total loans held-for-investment	8,418		9,173
Allowance for credit losses	(2,653)	(2,717)	(2,904)	(2,924)	(2,945)	(3,085)
Real estate loans: | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Loans and Leases Receivable Disclosure [Line Items]
Total commercial and industrial and other loans	3,728,671		3,847,461
Total loans held-for-investment	3,728,671		3,847,461
Real estate loans: | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Multifamily
Loans and Leases Receivable Disclosure [Line Items]
Total commercial and industrial and other loans	2,440,505		2,597,484
Total loans held-for-investment	2,440,505		2,597,484
Real estate loans: | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total commercial and industrial and other loans	894,523		889,801
Total loans held-for-investment	894,523		889,801
Real estate loans: | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | One-to-four family residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Total commercial and industrial and other loans	165,969		150,217
Total loans held-for-investment	165,969		150,217
Allowance for credit losses	(2,324)	(2,444)	(2,245)	(2,098)	(2,292)	(3,285)
Real estate loans: | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Home equity and lines of credit
Loans and Leases Receivable Disclosure [Line Items]
Total commercial and industrial and other loans	193,309		174,062
Total loans held-for-investment	193,309		174,062
Allowance for credit losses	(2,691)	(2,729)	(2,254)	(2,297)	(2,562)	(1,705)
Real estate loans: | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Construction and land
Loans and Leases Receivable Disclosure [Line Items]
Total commercial and industrial and other loans	34,365		35,897
Total loans held-for-investment	34,365		35,897
Allowance for credit losses	(95)	(98)	(103)	(106)	(108)	(149)
Commercial and industrial and other loans | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Loans and Leases Receivable Disclosure [Line Items]
Total commercial and industrial and other loans	163,257		165,590
Commercial and industrial loans | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Loans and Leases Receivable Disclosure [Line Items]
Total commercial and industrial and other loans	162,053		163,425
Total loans held-for-investment	162,053		163,425
Allowance for credit losses	(5,457)	(5,359)	(6,724)	(7,757)	(7,564)	(6,050)
Other loans | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Loans and Leases Receivable Disclosure [Line Items]
Total commercial and industrial and other loans	1,204		2,165
Total loans held-for-investment	1,204		2,165
Allowance for credit losses	$ (2)	$ (3)	$ (4)	$ (2)	$ (3)	$ (6)