Investment Securities - Schedule of Available-for-sale Investment Securities Portfolios (Details) - USD ($)	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	$ 1,381,414,000
Continuous unrealized losses existing for less than 12 months, unrealized losses	(17,185,000)
Continuous unrealized losses existing for greater than 12 months, fair value	2,475,398,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(495,133,000)
Total, fair value	3,856,812,000
Total, unrealized losses	(512,318,000)
Available-for-sale securities, at fair value	4,220,305,000	$ 4,141,482,000	$ 4,387,598,000
U.S. Treasury
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	0
Continuous unrealized losses existing for less than 12 months, unrealized losses	0
Continuous unrealized losses existing for greater than 12 months, fair value	0
Continuous unrealized losses existing for greater than 12 months, unrealized losses	0
Total, fair value	0
Total, unrealized losses	0
Available-for-sale securities, at fair value	12,994,000	37,907,000	61,175,000
U.S. government agencies
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	0
Continuous unrealized losses existing for less than 12 months, unrealized losses	0
Continuous unrealized losses existing for greater than 12 months, fair value	45,944,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(4,056,000)
Total, fair value	45,944,000
Total, unrealized losses	(4,056,000)
Available-for-sale securities, at fair value	45,944,000	44,945,000	45,715,000
Municipal
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	45,437,000
Continuous unrealized losses existing for less than 12 months, unrealized losses	(717,000)
Continuous unrealized losses existing for greater than 12 months, fair value	50,975,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(2,867,000)
Total, fair value	96,412,000
Total, unrealized losses	(3,584,000)
Available-for-sale securities, at fair value	188,149,000	184,593,000	140,590,000
Financial issuers
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	0
Continuous unrealized losses existing for less than 12 months, unrealized losses	0
Continuous unrealized losses existing for greater than 12 months, fair value	80,435,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(3,562,000)
Total, fair value	80,435,000
Total, unrealized losses	(3,562,000)
Available-for-sale securities, at fair value	80,435,000	80,169,000	75,732,000
Other
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	0
Continuous unrealized losses existing for less than 12 months, unrealized losses	0
Continuous unrealized losses existing for greater than 12 months, fair value	1,000,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	0
Total, fair value	1,000,000
Total, unrealized losses	0
Available-for-sale securities, at fair value	1,000,000	993,000	993,000
Residential mortgage-backed securities
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	1,279,995,000
Continuous unrealized losses existing for less than 12 months, unrealized losses	(15,142,000)
Continuous unrealized losses existing for greater than 12 months, fair value	2,224,823,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(467,114,000)
Total, fair value	3,504,818,000
Total, unrealized losses	(482,256,000)
Available-for-sale securities, at fair value	3,586,000,000	3,553,638,000	3,876,723,000
Commercial (multi-family) mortgage-backed securities
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	39,068,000
Continuous unrealized losses existing for less than 12 months, unrealized losses	(1,312,000)
Continuous unrealized losses existing for greater than 12 months, fair value	6,134,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(384,000)
Total, fair value	45,202,000
Total, unrealized losses	(1,696,000)
Available-for-sale securities, at fair value	56,627,000	18,332,000	15,676,000
Collateralized mortgage obligations
Available-for-sale securities
Continuous unrealized losses existing for less than 12 months, fair value	16,914,000
Continuous unrealized losses existing for less than 12 months, unrealized losses	(14,000)
Continuous unrealized losses existing for greater than 12 months, fair value	66,087,000
Continuous unrealized losses existing for greater than 12 months, unrealized losses	(17,150,000)
Total, fair value	83,001,000
Total, unrealized losses	(17,164,000)
Available-for-sale securities, at fair value	249,156,000	220,905,000	170,994,000
Mortgage-backed securities, subprime
Available-for-sale securities
Available-for-sale securities, at fair value	$ 0	$ 0	$ 0