Securities Available for Sale and Held to Maturity - Contractual Maturities of Available for Sale and Held to Maturity Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Securities Available for Sale, Amortized Cost [Abstract]
Due in one year or less	$ 99,995
Due after one year through five years	296,508
Due after five years through ten years	2,236
Due after ten years	3,567
Total amortized cost, before mortgage-backed securities	402,306
Mortgage-backed securities	1,498,674
Securities Available for Sale, Amortized Cost	1,900,980	$ 1,959,007
Securities Available for Sale, Estimated Fair Value [Abstract]
Due in one year or less	98,050
Due after one year through five years	274,584
Due after five years through ten years	2,021
Due after ten years	3,363
Total fair value, before mortgage-backed securities	378,018
Mortgage-backed securities	1,324,281
Total	1,702,299	1,762,878
Securities Held to Maturity, Amortized Cost [Abstract]
Due in one year or less	340
Due after one year through five years	29,261
Due after five years through ten years	0
Due after ten years	0
Total amortized cost, before mortgage-backed securities	29,601
Mortgage-backed securities	1,385,424
Securities Held to Maturity, Amortized Cost	1,415,025	1,426,279
Securities Held to Maturity, Estimated Fair Value [Abstract]
Due in one year or less	340
Due after one year through five years	28,746
Due after five years through ten years	0
Due after ten years	0
Total fair value, before mortgage-backed securities	29,086
Mortgage-backed securities	1,303,928
Total	$ 1,333,014	$ 1,355,504