Investment Securities - Gross Unrealized Losses on Available-for-sale Securities and the Related Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	$ 52,701	$ 318,639
Less than 12 months, unrealized losses	(784)	(9,576)
More than 12 months, fair value	592,403	342,354
More than 12 months, unrealized losses	(36,330)	(32,550)
Fair Value	645,104	660,993
Unrealized Losses	(37,114)	(42,126)
U.S. Treasury and government sponsored entities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	42,827	282,319
Less than 12 months, unrealized losses	(658)	(8,876)
More than 12 months, fair value	535,809	302,840
More than 12 months, unrealized losses	(34,922)	(30,546)
Fair Value	578,636	585,159
Unrealized Losses	(35,580)	(39,422)
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	0	13,216
Less than 12 months, unrealized losses	0	(43)
More than 12 months, fair value	6,431	4,394
More than 12 months, unrealized losses	(587)	(631)
Fair Value	6,431	17,610
Unrealized Losses	(587)	(674)
Collateralized loan obligations
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	9,874	22,309
Less than 12 months, unrealized losses	(126)	(632)
More than 12 months, fair value	49,354	35,120
More than 12 months, unrealized losses	(810)	(1,373)
Fair Value	59,228	57,429
Unrealized Losses	(936)	(2,005)
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	0	795
Less than 12 months, unrealized losses	0	(25)
More than 12 months, fair value	809	0
More than 12 months, unrealized losses	(11)	0
Fair Value	809	795
Unrealized Losses	$ (11)	$ (25)