Debt Securities Available-for-Sale - Gross Unrealized Losses on Mortgage-Backed Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	$ (37,689)	$ (4,637)
Estimated fair value, less than 12 months	970,107	689,869
Unrealized losses, 12 months or more	(5,898)	(466)
Estimated fair value, 12 months or more	83,588	21,328
Unrealized losses, total	(43,587)	(5,103)
Estimated fair value, total	1,053,695	711,197
U.S. Government agency securities
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	(1,642)	0
Estimated fair value, less than 12 months	73,358	0
Unrealized losses, 12 months or more	(127)	(54)
Estimated fair value, 12 months or more	1,444	2,290
Unrealized losses, total	(1,769)	(54)
Estimated fair value, total	74,802	2,290
GSE \| Pass-through Certificates
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	(24,602)	(2,543)
Estimated fair value, less than 12 months	490,569	417,291
Unrealized losses, 12 months or more	(668)	(318)
Estimated fair value, 12 months or more	7,927	14,625
Unrealized losses, total	(25,270)	(2,861)
Estimated fair value, total	498,496	431,916
GSE \| Real estate mortgage investment conduits (REMICs)
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	(6,077)	(1,350)
Estimated fair value, less than 12 months	246,515	125,725
Unrealized losses, 12 months or more	(3,405)	(94)
Estimated fair value, 12 months or more	60,905	4,413
Unrealized losses, total	(9,482)	(1,444)
Estimated fair value, total	307,420	130,138
Corporate bonds \| Other debt securities
Debt Securities, Available-for-sale [Line Items]
Unrealized losses, less than 12 months	(5,368)	(744)
Estimated fair value, less than 12 months	159,665	146,853
Unrealized losses, 12 months or more	(1,698)	0
Estimated fair value, 12 months or more	13,312	0
Unrealized losses, total	(7,066)	(744)
Estimated fair value, total	$ 172,977	$ 146,853

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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