Investment Securities - Contractual Maturities of Investment Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Available-for-sale securities
Due in one year or less, amortized cost	$ 53,162	$ 119,830
Due in one to five years, amortized cost	132,348	63,644
Due in five to ten years, amortized cost	82,040	115,734
Due after ten years, amortized cost	18,705	64,590
Amortized Cost	3,979,814	3,769,634
Due in one year or less, fair value	52,945	119,275
Due in one to five years, fair value	123,985	61,701
Due in five to ten years, fair value	76,869	105,076
Due after ten years, fair value	15,782	57,478
Fair Value	3,502,915	3,243,017
Held-to-maturity securities
Held-to-maturity securities, due in one year or less, amortized cost	5,169	1,340
Held-to-maturity securities, due in one to five years, amortized cost	109,602	94,705
Held-to-maturity securities, due in five to ten years, amortized cost	99,700	115,318
Held-to-maturity securities, due after ten years, amortized cost	352,474	365,510
Amortized Cost	3,857,263	3,641,055
Less: Allowance for credit losses	(347)	(488)
Held-to-maturity securities, net of allowance for credit losses	3,856,916	3,640,567
Held-to-maturity securities, due in one year or less, fair value	5,142	1,332
Held-to-maturity securities, due in one to five years, fair value	105,835	89,093
Held-to-maturity securities, due in five to ten years, fair value	98,718	113,758
Held-to-maturity securities, due after ten years, fair value	283,506	288,460
Fair Value	3,215,468	2,949,821
Mortgage-backed
Available-for-sale securities
Mortgage-backed, without single maturity date, amortized cost	3,693,559	3,405,836
Mortgage-backed, without single maturity date, fair value	3,233,334	2,899,487
Held-to-maturity securities
Mortgage-backed, amortized cost	3,290,318	3,064,182
Mortgage-backed, fair value	$ 2,722,267	$ 2,457,178