Investment Securities - Schedule of Gross Unrealized Losses on Investment Securities AFS (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	$ 40,410	$ 409,725
Less than 12 months, gross unrealized losses	(483)	(2,666)
12 months or longer, fair value	3,153,697	7,513,154
12 months or longer, gross unrealized losses	(381,427)	(1,331,466)
Total, fair value	3,194,107	7,922,879
Total, gross unrealized losses	(381,910)	(1,334,132)
U.S. Treasury 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	0
12 months or longer, gross unrealized losses	0
Total, fair value	0
Total, gross unrealized losses	0
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	29,613	28,940
12 months or longer, gross unrealized losses	(380)	(1,053)
Total, fair value	29,613	28,940
Total, gross unrealized losses	(380)	(1,053)
Mortgage-backed securities issued by U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	40,410	159,402
Less than 12 months, gross unrealized losses	(483)	(1,268)
12 months or longer, fair value	621,818	565,358
12 months or longer, gross unrealized losses	(86,195)	(96,717)
Total, fair value	662,228	724,760
Total, gross unrealized losses	(86,678)	(97,985)
Mortgage-backed securities issued by U.S. Government sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	0	215,917
Less than 12 months, gross unrealized losses	0	(1,193)
12 months or longer, fair value	1,655,295	6,045,914
12 months or longer, gross unrealized losses	(178,671)	(1,093,019)
Total, fair value	1,655,295	6,261,831
Total, gross unrealized losses	(178,671)	(1,094,212)
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	0	0
Less than 12 months, gross unrealized losses	0	0
12 months or longer, fair value	554,911	587,595
12 months or longer, gross unrealized losses	(89,295)	(104,892)
Total, fair value	554,911	587,595
Total, gross unrealized losses	(89,295)	(104,892)
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	34,406
Less than 12 months, gross unrealized losses	0	(205)
12 months or longer, fair value	283,330	276,675
12 months or longer, gross unrealized losses	(26,532)	(35,448)
Total, fair value	283,330	311,081
Total, gross unrealized losses	(26,532)	(35,653)
Corporate debt securities and other debt 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	8,730	8,672
12 months or longer, gross unrealized losses	(354)	(337)
Total, fair value	8,730	8,672
Total, gross unrealized losses	$ (354)	$ (337)

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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