Investment Securities - Schedule of Investment Securities (Details) - USD ($)	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024
Available-for-sale securities
Amortized Cost	$ 4,729,234,000	$ 4,725,539,000	$ 4,942,360,000
Gross Unrealized Gains	3,389,000	2,071,000	2,001,000
Gross Unrealized Losses	(512,318,000)	(586,128,000)	(556,763,000)
Fair Value	4,220,305,000	4,141,482,000	4,387,598,000
Held-to-maturity securities
Amortized Cost	3,564,936,000	3,613,720,000	3,810,344,000
Gross Unrealized Gains	2,172,000	1,066,000	697,000
Gross Unrealized Losses	(644,295,000)	(704,236,000)	(699,087,000)
Fair Value	2,922,813,000	2,910,550,000	3,111,954,000
Less: Allowance for credit losses	(446,000)	(457,000)	(329,000)
Held-to-maturity securities, net of allowance for credit losses	3,564,490,000	3,613,263,000	3,810,015,000
Equity securities with readily determinable fair value
Amortized Cost	272,400,000	220,758,000	123,421,000
Gross Unrealized Gains	5,254,000	2,905,000	4,480,000
Gross Unrealized Losses	(7,212,000)	(8,251,000)	(8,124,000)
Fair Value	270,442,000	215,412,000	119,777,000
U.S. Treasury
Available-for-sale securities
Amortized Cost	12,943,000	37,858,000	61,185,000
Gross Unrealized Gains	51,000	49,000	0
Gross Unrealized Losses	0	0	(10,000)
Fair Value	12,994,000	37,907,000	61,175,000
U.S. government agencies
Available-for-sale securities
Amortized Cost	50,000,000	50,000,000	50,000,000
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	(4,056,000)	(5,055,000)	(4,285,000)
Fair Value	45,944,000	44,945,000	45,715,000
Held-to-maturity securities
Amortized Cost	313,539,000	313,539,000	336,463,000
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	(62,627,000)	(69,127,000)	(69,998,000)
Fair Value	250,912,000	244,412,000	266,465,000
Municipal
Available-for-sale securities
Amortized Cost	190,670,000	188,405,000	144,752,000
Gross Unrealized Gains	1,063,000	528,000	569,000
Gross Unrealized Losses	(3,584,000)	(4,340,000)	(4,731,000)
Fair Value	188,149,000	184,593,000	140,590,000
Held-to-maturity securities
Amortized Cost	158,307,000	161,016,000	168,490,000
Gross Unrealized Gains	303,000	243,000	258,000
Gross Unrealized Losses	(4,964,000)	(5,290,000)	(4,709,000)
Fair Value	153,646,000	155,969,000	164,039,000
Corporate notes
Held-to-maturity securities
Amortized Cost	56,681,000	56,851,000	57,372,000
Gross Unrealized Gains	14,000	8,000	8,000
Gross Unrealized Losses	(1,367,000)	(1,870,000)	(3,358,000)
Fair Value	55,328,000	54,989,000	54,022,000
Financial issuers
Available-for-sale securities
Amortized Cost	83,997,000	83,997,000	83,996,000
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	(3,562,000)	(3,828,000)	(8,264,000)
Fair Value	80,435,000	80,169,000	75,732,000
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	(7,000)	(7,000)
Fair Value	1,000,000	993,000	993,000
Residential mortgage-backed securities
Available-for-sale securities
Amortized Cost	4,067,349,000	4,106,641,000	4,396,962,000
Gross Unrealized Gains	907,000	284,000	480,000
Gross Unrealized Losses	(482,256,000)	(553,287,000)	(520,719,000)
Fair Value	3,586,000,000	3,553,638,000	3,876,723,000
Held-to-maturity securities
Amortized Cost	2,825,859,000	2,864,927,000	3,007,304,000
Gross Unrealized Gains	1,072,000	0	0
Gross Unrealized Losses	(555,525,000)	(605,014,000)	(597,758,000)
Fair Value	2,271,406,000	2,259,913,000	2,409,546,000
Commercial (multi-family) mortgage-backed securities
Available-for-sale securities
Amortized Cost	58,205,000	19,064,000	16,225,000
Gross Unrealized Gains	118,000	23,000	28,000
Gross Unrealized Losses	(1,696,000)	(755,000)	(577,000)
Fair Value	56,627,000	18,332,000	15,676,000
Held-to-maturity securities
Amortized Cost	6,351,000	6,364,000	6,401,000
Gross Unrealized Gains	20,000	0	0
Gross Unrealized Losses	(134,000)	(252,000)	(281,000)
Fair Value	6,237,000	6,112,000	6,120,000
Collateralized mortgage obligations
Available-for-sale securities
Amortized Cost	265,070,000	238,574,000	188,240,000
Gross Unrealized Gains	1,250,000	1,187,000	924,000
Gross Unrealized Losses	(17,164,000)	(18,856,000)	(18,170,000)
Fair Value	249,156,000	220,905,000	170,994,000
Held-to-maturity securities
Amortized Cost	204,199,000	211,023,000	234,314,000
Gross Unrealized Gains	763,000	815,000	431,000
Gross Unrealized Losses	(19,678,000)	(22,683,000)	(22,983,000)
Fair Value	185,284,000	189,155,000	211,762,000
Mortgage-backed securities, subprime
Available-for-sale securities
Fair Value	$ 0	$ 0	$ 0