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, 2023	Dec. 31, 2022
Securities Available for Sale, Amortized Cost [Abstract]
Due in one year or less	$ 20,056
Due after one year through five years	389,619
Due after five years through ten years	14,018
Due after ten years	4,698
Total amortized cost, before mortgage-backed securities	428,391
Mortgage-backed securities	1,771,864
Securities Available for Sale, Amortized Cost	2,200,255	$ 2,270,709
Securities Available for Sale, Estimated Fair Value [Abstract]
Due in one year or less	19,984
Due after one year through five years	361,580
Due after five years through ten years	13,047
Due after ten years	4,453
Total fair value, before mortgage-backed securities	399,064
Mortgage-backed securities	1,585,098
Total	1,984,162	2,024,082
Securities Held to Maturity, Amortized Cost [Abstract]
Due in one year or less	4,166
Due after one year through five years	341
Due after five years through ten years	28,486
Due after ten years	0
Total amortized cost, before mortgage-backed securities	32,993
Mortgage-backed securities	1,441,345
Securities Held to Maturity, Amortized Cost	1,474,338	1,494,514
Securities Held to Maturity, Estimated Fair Value [Abstract]
Due in one year or less	4,170
Due after one year through five years	340
Due after five years through ten years	28,847
Due after ten years	0
Total fair value, before mortgage-backed securities	33,357
Mortgage-backed securities	1,373,048
Total	$ 1,406,405	$ 1,406,589