Investment Securities - Schedule of Investment Securities (Details) - USD ($)	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Available-for-sale securities
Amortized Cost	$ 4,320,843,000	$ 3,979,814,000	$ 4,315,723,000
Gross Unrealized Gains	11,552,000	3,525,000	50,000
Gross Unrealized Losses	(420,163,000)	(480,424,000)	(703,938,000)
Fair Value	3,912,232,000	3,502,915,000	3,611,835,000
Held-to-maturity securities
Amortized Cost	3,677,899,000	3,857,263,000	3,909,531,000
Gross Unrealized Gains	7,526,000	3,472,000	123,000
Gross Unrealized Losses	(563,605,000)	(645,267,000)	(851,695,000)
Fair Value	3,121,820,000	3,215,468,000	3,057,959,000
Less: Allowance for credit losses	(479,000)	(347,000)	(381,000)
Held-to-maturity securities, net of allowance for credit losses	3,677,420,000	3,856,916,000	3,909,150,000
Equity securities with readily determinable fair value
Amortized Cost	127,700,000	143,312,000	140,749,000
Gross Unrealized Gains	4,313,000	3,500,000	3,290,000
Gross Unrealized Losses	(6,703,000)	(7,544,000)	(9,729,000)
Fair Value	125,310,000	139,268,000	134,310,000
U.S. Treasury
Available-for-sale securities
Amortized Cost	98,151,000	6,960,000	4,930,000
Gross Unrealized Gains	172,000	8,000	1,000
Gross Unrealized Losses	0	0	0
Fair Value	98,323,000	6,968,000	4,931,000
U.S. government agencies
Available-for-sale securities
Amortized Cost	50,000,000	50,000,000	80,000,000
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	(2,346,000)	(4,876,000)	(7,570,000)
Fair Value	47,654,000	45,124,000	72,430,000
Held-to-maturity securities
Amortized Cost	314,578,000	336,468,000	339,598,000
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	(56,198,000)	(67,058,000)	(87,897,000)
Fair Value	258,380,000	269,410,000	251,701,000
Municipal
Available-for-sale securities
Amortized Cost	201,701,000	144,299,000	177,208,000
Gross Unrealized Gains	1,392,000	657,000	49,000
Gross Unrealized Losses	(2,881,000)	(3,998,000)	(8,734,000)
Fair Value	200,212,000	140,958,000	168,523,000
Held-to-maturity securities
Amortized Cost	165,141,000	172,933,000	176,262,000
Gross Unrealized Gains	488,000	565,000	123,000
Gross Unrealized Losses	(2,910,000)	(3,778,000)	(11,230,000)
Fair Value	162,719,000	169,720,000	165,155,000
Corporate notes
Held-to-maturity securities
Amortized Cost	57,025,000	57,544,000	57,717,000
Gross Unrealized Gains	0	7,000	0
Gross Unrealized Losses	(1,953,000)	(3,480,000)	(4,849,000)
Fair Value	55,072,000	54,071,000	52,868,000
Financial issuers
Available-for-sale securities
Amortized Cost	83,997,000	83,996,000	83,995,000
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	(4,880,000)	(8,456,000)	(8,368,000)
Fair Value	79,117,000	75,540,000	75,627,000
Other
Available-for-sale securities
Amortized Cost	1,000,000	1,000,000	1,000,000
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	0	(9,000)	(21,000)
Fair Value	1,000,000	991,000	979,000
Residential mortgage-backed securities
Available-for-sale securities
Amortized Cost	3,694,382,000	3,505,012,000	3,862,871,000
Gross Unrealized Gains	8,143,000	1,392,000	0
Gross Unrealized Losses	(394,844,000)	(446,784,000)	(656,135,000)
Fair Value	3,307,681,000	3,059,620,000	3,206,736,000
Held-to-maturity securities
Amortized Cost	2,915,018,000	3,042,828,000	3,082,314,000
Gross Unrealized Gains	5,541,000	1,922,000	0
Gross Unrealized Losses	(485,115,000)	(549,265,000)	(717,444,000)
Fair Value	2,435,444,000	2,495,485,000	2,364,870,000
Commercial (multi-family) mortgage-backed securities
Available-for-sale securities
Amortized Cost	19,088,000	13,201,000	13,179,000
Gross Unrealized Gains	308,000	68,000	0
Gross Unrealized Losses	(255,000)	(289,000)	(802,000)
Fair Value	19,141,000	12,980,000	12,377,000
Held-to-maturity securities
Amortized Cost	6,379,000	6,415,000	6,425,000
Gross Unrealized Gains	40,000	0	0
Gross Unrealized Losses	(126,000)	(184,000)	(477,000)
Fair Value	6,293,000	6,231,000	5,948,000
Collateralized mortgage obligations
Available-for-sale securities
Amortized Cost	172,524,000	175,346,000	92,540,000
Gross Unrealized Gains	1,537,000	1,400,000	0
Gross Unrealized Losses	(14,957,000)	(16,012,000)	(22,308,000)
Fair Value	159,104,000	160,734,000	70,232,000
Held-to-maturity securities
Amortized Cost	219,758,000	241,075,000	247,215,000
Gross Unrealized Gains	1,457,000	978,000	0
Gross Unrealized Losses	(17,303,000)	(21,502,000)	(29,798,000)
Fair Value	203,912,000	220,551,000	217,417,000
Mortgage-backed securities, subprime
Available-for-sale securities
Fair Value	$ 0	$ 0	$ 0