Investment Securities - Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Debt Securities Held to Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	$ 3,532,220	$ 3,740,413
Gross Unrealized Gains	2,107	6,651
Gross Unrealized Losses	(506,043)	(444,752)
Fair Value	3,028,284	3,302,312
Held-to-maturity, allowance for credit loss	647	1,205	$ 1,646	$ 1,165
Net Carrying Value	3,531,573	3,739,208
U.S. Treasury securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	25,480	26,232
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(19)	(254)
Fair Value	25,461	25,978
Held-to-maturity, allowance for credit loss	0	0
Net Carrying Value	25,480	26,232
U.S. government agency securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	301,315	305,996
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(49,013)	(44,441)
Fair Value	252,302	261,555
Held-to-maturity, allowance for credit loss	0	0
Net Carrying Value	301,315	305,996
Obligations of states and state agencies
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	68,025	88,556
Gross Unrealized Gains	0	552
Gross Unrealized Losses	(5,335)	(4,155)
Fair Value	62,690	84,953
Held-to-maturity, allowance for credit loss	2	395
Net Carrying Value	68,023	88,161
Municipal bonds
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	304,464	316,914
Gross Unrealized Gains	9	40
Gross Unrealized Losses	(20,802)	(14,380)
Fair Value	283,671	302,574
Held-to-maturity, allowance for credit loss	48	49
Net Carrying Value	304,416	316,865
Obligations of states and political subdivisions
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	372,489	405,470
Gross Unrealized Gains	9	592
Gross Unrealized Losses	(26,137)	(18,535)
Fair Value	346,361	387,527
Held-to-maturity, allowance for credit loss	50	444
Net Carrying Value	372,439	405,026
Residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	2,710,642	2,885,303
Gross Unrealized Gains	2,088	6,059
Gross Unrealized Losses	(420,582)	(369,436)
Fair Value	2,292,148	2,521,926
Held-to-maturity, allowance for credit loss	0	0
Net Carrying Value	2,710,642	2,885,303
Trust preferred securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	36,081	37,062
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(6,936)	(6,412)
Fair Value	29,145	30,650
Held-to-maturity, allowance for credit loss	414	506
Net Carrying Value	35,667	36,556
Corporate and other debt securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	86,213	80,350
Gross Unrealized Gains	10	0
Gross Unrealized Losses	(3,356)	(5,674)
Fair Value	82,867	74,676
Held-to-maturity, allowance for credit loss	183	255
Net Carrying Value	$ 86,030	$ 80,095