Securities Available for Sale and Held to Maturity - Contractual Maturities of Available for Sale and Held to Maturity Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Securities Available for Sale, Amortized Cost [Abstract]
Due in one year or less	$ 42,751
Due after one year through five years	75,223
Due after five years through ten years	99,946
Total amortized cost, before mortgage-backed securities	217,920
Mortgage-backed securities	1,473,635
Securities Available for Sale, Amortized Cost	1,691,555	$ 1,959,007
Securities Available for Sale, Estimated Fair Value [Abstract]
Due in one year or less	42,962
Due after one year through five years	76,656
Due after five years through ten years	102,355
Total fair value, before mortgage-backed securities	221,973
Mortgage-backed securities	1,503,822
Total	1,725,795	1,762,878
Securities Held to Maturity, Amortized Cost [Abstract]
Due in one year or less	0
Due after one year through five years	29,648
Due after five years through ten years	0
Total amortized cost, before mortgage-backed securities	29,648
Mortgage-backed securities	1,328,710
Securities Held to Maturity, Amortized Cost	1,358,358	1,426,279
Securities Held to Maturity, Estimated Fair Value [Abstract]
Due in one year or less	0
Due after one year through five years	29,880
Due after five years through ten years	0
Total fair value, before mortgage-backed securities	29,880
Mortgage-backed securities	1,286,287
Total	$ 1,316,167	$ 1,355,504