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Investment Securities - Schedule of Debt Securities Held-to-Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost	$ 7,695,049		$ 7,969,672
Gross Unrealized Gains	16,683		25,062
Gross Unrealized Losses	(901,867)		(826,151)
Fair Value	6,809,865		7,168,583
Allowance for Credit Losses	(70)	$ (96)	(97)	$ (102)	$ (109)	$ (171)
Net Carrying Value	7,694,979		7,969,575
Held-to-maturity Securities
Financing Receivable, Credit Quality Indicator [Line Items]
Interest receivable	27,100		28,100
Agency CMO
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost	15,063		16,791
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(1,141)		(1,071)
Fair Value	13,922		15,720
Allowance for Credit Losses	0		0
Net Carrying Value	15,063		16,791
Agency MBS
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost	2,569,979		2,767,869
Gross Unrealized Gains	15,841		24,073
Gross Unrealized Losses	(236,162)		(226,089)
Fair Value	2,349,658		2,565,853
Allowance for Credit Losses	0		0
Net Carrying Value	2,569,979		2,767,869
Agency CMBS
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost	4,253,522		4,295,308
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(635,039)		(567,040)
Fair Value	3,618,483		3,728,268
Allowance for Credit Losses	0		0
Net Carrying Value	4,253,522		4,295,308
Municipal bonds and notes
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost	794,654		824,734
Gross Unrealized Gains	842		989
Gross Unrealized Losses	(28,229)		(30,461)
Fair Value	767,267		795,262
Allowance for Credit Losses	(70)		(97)
Net Carrying Value	794,584		824,637
CMBS
Financing Receivable, Credit Quality Indicator [Line Items]
Amortized Cost	61,831		64,970
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(1,296)		(1,490)
Fair Value	60,535		63,480
Allowance for Credit Losses	0		0
Net Carrying Value	$ 61,831		$ 64,970