Investment Securities - Summary of Investment Securities (Detail) - USD ($) $ in Thousands		Mar. 31, 2025	Dec. 31, 2024
Schedule of Investments [Line Items]
Amortized cost		$ 9,941,377	$ 9,720,415
Unrealized Gains		33,095	12,952
Unrealized Losses		(613,508)	(725,900)
Allowance for Credit Losses		(867)	(867)
Fair Value	[1]	9,360,097	9,006,600
Debt Securities, Available-For-Sale
Schedule of Investments [Line Items]
Interest receivable		37,500	35,200
Government agency debentures
Schedule of Investments [Line Items]
Amortized cost		222,789	222,767
Unrealized Gains		0	0
Unrealized Losses		(30,448)	(36,341)
Allowance for Credit Losses		0	0
Fair Value		192,341	186,426
Municipal bonds and notes
Schedule of Investments [Line Items]
Amortized cost		122,999	123,885
Unrealized Gains		2	2
Unrealized Losses		(13,707)	(13,011)
Allowance for Credit Losses		0	0
Fair Value		109,294	110,876
Agency CMO
Schedule of Investments [Line Items]
Amortized cost		30,855	32,193
Unrealized Gains		0	0
Unrealized Losses		(2,570)	(3,150)
Allowance for Credit Losses		0	0
Fair Value		28,285	29,043
Agency MBS
Schedule of Investments [Line Items]
Amortized cost		4,927,652	4,760,541
Unrealized Gains		28,536	11,654
Unrealized Losses		(198,033)	(252,410)
Allowance for Credit Losses		0	0
Fair Value		4,758,155	4,519,785
Agency CMBS
Schedule of Investments [Line Items]
Amortized cost		3,476,934	3,400,021
Unrealized Gains		4,199	84
Unrealized Losses		(324,833)	(365,713)
Allowance for Credit Losses		0	0
Fair Value		3,156,300	3,034,392
CMBS
Schedule of Investments [Line Items]
Amortized cost		632,333	630,985
Unrealized Gains		97	411
Unrealized Losses		(3,079)	(6,008)
Allowance for Credit Losses		0	0
Fair Value		629,351	625,388
Corporate debt
Schedule of Investments [Line Items]
Amortized cost		474,599	496,087
Unrealized Gains		261	801
Unrealized Losses		(36,063)	(43,755)
Allowance for Credit Losses		(867)	(867)
Fair Value		437,930	452,266
Private label MBS
Schedule of Investments [Line Items]
Amortized cost		43,355	44,081
Unrealized Gains		0	0
Unrealized Losses		(4,197)	(4,862)
Allowance for Credit Losses		0	0
Fair Value		39,158	39,219
Other
Schedule of Investments [Line Items]
Amortized cost		9,861	9,855
Unrealized Gains		0	0
Unrealized Losses		(578)	(650)
Allowance for Credit Losses		0	0
Fair Value		$ 9,283	$ 9,205

[1] Investment securities available-for-sale had an amortized cost basis of $9,941,377 at March 31, 2025, and $9,720,415 at December 31, 2024.