Debt Securities Available-for-Sale - Gross Unrealized Losses on Mortgage-Backed Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	$ (20)	$ (410)
Estimated fair value, less than 12 months	35,067	112,741
Unrealized losses, 12 months or more	(17,339)	(29,916)
Estimated fair value, 12 months or more	353,344	511,839
Unrealized losses, total	(17,359)	(30,326)
Estimated fair value, total	388,411	624,580
U.S. Government agency securities
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	0	0
Estimated fair value, less than 12 months	0	0
Unrealized losses, 12 months or more	(51)	(386)
Estimated fair value, 12 months or more	556	75,348
Unrealized losses, total	(51)	(386)
Estimated fair value, total	556	75,348
Pass-through Certificates | GSE
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	0	(125)
Estimated fair value, less than 12 months	1,301	7,329
Unrealized losses, 12 months or more	(12,330)	(20,903)
Estimated fair value, 12 months or more	205,028	254,163
Unrealized losses, total	(12,330)	(21,028)
Estimated fair value, total	206,329	261,492
Real estate mortgage investment conduits (REMICs) | GSE
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	(20)	(285)
Estimated fair value, less than 12 months	33,283	105,412
Unrealized losses, 12 months or more	(4,592)	(7,689)
Estimated fair value, 12 months or more	129,123	164,262
Unrealized losses, total	(4,612)	(7,974)
Estimated fair value, total	162,406	269,674
Other debt securities | Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	0
Estimated fair value, less than 12 months	483
Unrealized losses, 12 months or more	0
Estimated fair value, 12 months or more	0
Unrealized losses, total	0
Estimated fair value, total	483
Other debt securities | Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	0	0
Estimated fair value, less than 12 months	0	0
Unrealized losses, 12 months or more	(366)	(938)
Estimated fair value, 12 months or more	18,637	18,066
Unrealized losses, total	(366)	(938)
Estimated fair value, total	$ 18,637	$ 18,066