Securities Available for Sale and Held to Maturity - Contractual Maturities of Available for Sale and Held to Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Securities Available for Sale, Amortized Cost [Abstract]
Due in one year or less	$ 65,199
Due after one year through five years	331,225
Due after five years through ten years	2,356
Due after ten years	3,606
Total amortized cost, before mortgage-backed securities	402,386
Mortgage-backed securities	1,556,621
Securities Available for Sale, Amortized Cost	1,959,007	$ 2,270,709
Securities Available for Sale, Estimated Fair Value [Abstract]
Due in one year or less	63,501
Due after one year through five years	309,108
Due after five years through ten years	2,151
Due after ten years	3,400
Total fair value, before mortgage-backed securities	378,160
Mortgage-backed securities	1,384,718
Total	1,762,878	2,024,082
Securities Held to Maturity, Amortized Cost [Abstract]
Due in one year or less	340
Due after one year through five years	29,068
Due after five years through ten years	0
Due after ten years	0
Total amortized cost, before mortgage-backed securities	29,408
Mortgage-backed securities	1,396,871
Securities Held to Maturity, Amortized Cost	1,426,279	1,494,514
Securities Held to Maturity, Estimated Fair Value [Abstract]
Due in one year or less	340
Due after one year through five years	29,042
Due after five years through ten years	0
Due after ten years	0
Total fair value, before mortgage-backed securities	29,382
Mortgage-backed securities	1,326,122
Total	$ 1,355,504	$ 1,406,589