Investment Securities - Schedule of Gross Unrealized Losses on Investment Securities AFS (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	$ 28,151	$ 2,979,465
Less than 12 months, gross unrealized losses	(176)	(37,202)
12 months or longer, fair value	3,085,405	2,956,231
12 months or longer, gross unrealized losses	(371,368)	(500,723)
Total, fair value	3,113,556	5,935,696
Total, gross unrealized losses	(371,544)	(537,925)
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value		716,367
Less than 12 months, gross unrealized losses		(4,824)
12 months or longer, fair value		0
12 months or longer, gross unrealized losses		0
Total, fair value		716,367
Total, gross unrealized losses		(4,824)
U.S. Government agency securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	0	0
Less than 12 months, gross unrealized losses	0	0
12 months or longer, fair value	29,857	29,163
12 months or longer, gross unrealized losses	(138)	(830)
Total, fair value	29,857	29,163
Total, gross unrealized losses	(138)	(830)
Mortgage-backed securities issued by U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	0	716,268
Less than 12 months, gross unrealized losses	0	(8,431)
12 months or longer, fair value	611,363	577,468
12 months or longer, gross unrealized losses	(89,072)	(112,958)
Total, fair value	611,363	1,293,736
Total, gross unrealized losses	(89,072)	(121,389)
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	0	456,887
Less than 12 months, gross unrealized losses	0	(12,503)
12 months or longer, fair value	1,600,160	1,542,618
12 months or longer, gross unrealized losses	(176,679)	(248,412)
Total, fair value	1,600,160	1,999,505
Total, gross unrealized losses	(176,679)	(260,915)
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	28,151	29,040
Less than 12 months, gross unrealized losses	(176)	(820)
12 months or longer, fair value	491,047	521,161
12 months or longer, gross unrealized losses	(84,152)	(106,432)
Total, fair value	519,198	550,201
Total, gross unrealized losses	(84,328)	(107,252)
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	0	1,060,903
Less than 12 months, gross unrealized losses	0	(10,624)
12 months or longer, fair value	352,978	276,850
12 months or longer, gross unrealized losses	(21,327)	(31,952)
Total, fair value	352,978	1,337,753
Total, gross unrealized losses	$ (21,327)	(42,576)
Corporate debt securities and other debt securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value		0
Less than 12 months, gross unrealized losses		0
12 months or longer, fair value		8,971
12 months or longer, gross unrealized losses		(139)
Total, fair value		8,971
Total, gross unrealized losses		$ (139)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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