Securities - Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Amortized Cost
Due within one year	$ 230
Due after one year through five years	12,007
Due after five years through ten years	186,144
Due after ten years	80,129
Amortized Cost	1,006,543	$ 1,030,105
Fair Value
Due within one year	230
Due after one year through five years	11,528
Due after five years through ten years	166,048
Due after ten years	69,129
Fair Value	928,696	961,870
Amortized Cost
Due within one year	7,235
Due after one year through five years	73,896
Due after five years through ten years	123,963
Due after ten years	117,477
Amortized Cost	2,900,216	2,635,495
Fair Value
Due within one year	7,247
Due after one year through five years	74,540
Due after five years through ten years	123,220
Due after ten years	119,256
Fair Value	2,809,647	2,560,818
Residential mortgage backed securities:
Amortized Cost
Amortized Cost	312,961	320,258
Fair Value
Fair Value	289,613	301,658
Other debt securities
Amortized Cost
Without single maturity date, amortized cost	42,947
Amortized Cost	42,947	47,413
Fair Value
Without single maturity date, fair value	40,547
Fair Value	40,547	45,351
Amortized Cost
Debt securities, without fixed maturity, amortized cost	286,866
Amortized Cost	336,708	349,132
Fair Value
Debt securities, without fixed maturity, fair value	285,946
Fair Value	335,567	348,355
Agency mortgage-backed securities | Residential mortgage backed securities:
Amortized Cost
Without single maturity date, amortized cost	313,373
Amortized Cost	313,373	323,993
Fair Value
Without single maturity date, fair value	300,932
Fair Value	300,932	313,963
Amortized Cost
Debt securities, without fixed maturity, amortized cost	1,045,352
Amortized Cost	1,045,352	793,154
Fair Value
Debt securities, without fixed maturity, fair value	1,029,101
Fair Value	1,029,101	783,149
Agency mortgage-backed securities | Commercial mortgage-backed securities:
Amortized Cost
Without single maturity date, amortized cost	16,901
Amortized Cost	16,901	16,938
Fair Value
Without single maturity date, fair value	14,822
Fair Value	14,822	14,879
Amortized Cost
Debt securities, without fixed maturity, amortized cost	99,305
Amortized Cost	99,305	100,314
Fair Value
Debt securities, without fixed maturity, fair value	99,047
Fair Value	99,047	99,837
Collateralized mortgage obligations | Residential mortgage backed securities:
Amortized Cost
Without single maturity date, amortized cost	312,961
Fair Value
Without single maturity date, fair value	289,613
Amortized Cost
Debt securities, without fixed maturity, amortized cost	727,087
Amortized Cost	727,087	706,986
Fair Value
Debt securities, without fixed maturity, fair value	668,068
Fair Value	668,068	651,904
Collateralized mortgage obligations | Commercial mortgage-backed securities:
Amortized Cost
Without single maturity date, amortized cost	41,851
Amortized Cost	41,851	42,079
Fair Value
Without single maturity date, fair value	35,847
Fair Value	35,847	36,082
Amortized Cost
Debt securities, without fixed maturity, amortized cost	419,035
Amortized Cost	419,035	419,356
Fair Value
Debt securities, without fixed maturity, fair value	403,222
Fair Value	$ 403,222	$ 404,788