Investment Securities - Schedule of Amortized Cost and Fair Value by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Amortized Cost
Due in One Year or Less	$ 551,899
Due after One Year through Five Years	296,138
Due after Five Years through Ten Years	278,805
Due after Ten Years	49,198
Amortized Cost	1,176,040	$ 2,904,745
Fair Value
Due in One Year or Less	552,207
Due after One Year through Five Years	292,597
Due after Five Years through Ten Years	246,344
Due after Ten Years	48,923
Total	1,140,071	2,601,013
Amortized Cost
Due in One Year or Less	0
Due after One Year through Five Years	28,271
Due after Five Years through Ten Years	41,467
Due after Ten Years	1,659,929
Amortized Cost	1,729,667	1,388,146
Fair Value
Due in One Year or Less	0
Due after One Year through Five Years	26,645
Due after Five Years through Ten Years	37,342
Due after Ten Years	1,421,519
Total	1,485,506	1,097,096
Amortized Cost
Due in One Year or Less	551,899
Due after One Year through Five Years	324,409
Due after Five Years through Ten Years	320,272
Due after Ten Years	1,709,127
Total	2,905,707
Fair Value
Due in One Year or Less	552,207
Due after One Year through Five Years	319,242
Due after Five Years through Ten Years	283,686
Due after Ten Years	1,470,442
Estimated Fair Value	2,625,577
Treasury
Amortized Cost
Due in One Year or Less	538,899
Due after One Year through Five Years	0
Due after Five Years through Ten Years	0
Due after Ten Years	0
Amortized Cost	538,899	49,156
Fair Value
Due in One Year or Less	539,256
Due after One Year through Five Years	0
Due after Five Years through Ten Years	0
Due after Ten Years	0
Total	539,256	47,017
Agency
Amortized Cost
Due in One Year or Less	0
Due after One Year through Five Years	0
Due after Five Years through Ten Years	1,190
Due after Ten Years	751
Amortized Cost	1,941	485,331
Fair Value
Due in One Year or Less	0
Due after One Year through Five Years	0
Due after Five Years through Ten Years	1,149
Due after Ten Years	719
Total	1,868	431,438
Corporate
Amortized Cost
Due in One Year or Less	13,000
Due after One Year through Five Years	254,872
Due after Five Years through Ten Years	213,627
Due after Ten Years	0
Amortized Cost	481,499	586,652
Fair Value
Due in One Year or Less	12,951
Due after One Year through Five Years	251,485
Due after Five Years through Ten Years	181,907
Due after Ten Years	0
Total	446,343	542,548
Collateralized mortgage obligations
Amortized Cost
Due in One Year or Less	0
Due after One Year through Five Years	41,266
Due after Five Years through Ten Years	63,988
Due after Ten Years	48,447
Amortized Cost	153,701	829,928
Fair Value
Due in One Year or Less	0
Due after One Year through Five Years	41,112
Due after Five Years through Ten Years	63,288
Due after Ten Years	48,204
Total	152,604	764,229
Amortized Cost
Due in One Year or Less	0
Due after One Year through Five Years	101
Due after Five Years through Ten Years	0
Due after Ten Years	334,896
Amortized Cost	334,997
Fair Value
Due in One Year or Less	0
Due after One Year through Five Years	101
Due after Five Years through Ten Years	0
Due after Ten Years	326,891
Total	326,992
Municipal bonds
Amortized Cost
Due in One Year or Less	0
Due after One Year through Five Years	26,257
Due after Five Years through Ten Years	37,985
Due after Ten Years	1,082,002
Amortized Cost	1,146,244	1,148,055
Fair Value
Due in One Year or Less	0
Due after One Year through Five Years	24,543
Due after Five Years through Ten Years	33,749
Due after Ten Years	882,284
Total	940,576	890,626
Mortgage-backed securities
Amortized Cost
Amortized Cost		953,678
Fair Value
Total		815,781
Amortized Cost
Due in One Year or Less	0
Due after One Year through Five Years	1,913
Due after Five Years through Ten Years	3,482
Due after Ten Years	226,762
Amortized Cost	232,157	231,692
Fair Value
Due in One Year or Less	0
Due after One Year through Five Years	2,001
Due after Five Years through Ten Years	3,593
Due after Ten Years	196,075
Total	201,669	$ 198,071
Other
Amortized Cost
Due in One Year or Less	0
Due after One Year through Five Years	0
Due after Five Years through Ten Years	0
Due after Ten Years	16,269
Amortized Cost	16,269
Fair Value
Due in One Year or Less	0
Due after One Year through Five Years	0
Due after Five Years through Ten Years	0
Due after Ten Years	16,269
Total	$ 16,269