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INVESTMENT SECURITIES - Summary of Amortized Cost and Approximate Fair Value of Investment Securities (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2025	Jun. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,045,324	$ 2,045,324		$ 2,087,881
Allowance for Credit Losses	(24,064)	(24,064)	$ (17,356)	(7,604)	$ (4,639)	$ (5,339)	$ (3,952)
Gross Unrealized Gains	9,915	9,915		732
Gross Unrealized Losses	(51,343)	(51,343)		(95,571)
Fair Value	1,979,832	1,979,832		1,985,438
Equity securities	30,988	30,988		34,256
Total investment securities, at fair value	2,010,820	2,010,820		2,019,694
Available-for-sale debt securities, accrued interest	9,400	9,400		15,000
Impairment loss on securities without a readily determinable fair value	0	2,300
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	281,612	281,612		14,820
Allowance for Credit Losses	(196)	(196)	(584)	(362)	(307)	(367)	(483)
Gross Unrealized Gains	800	800		0
Gross Unrealized Losses	(377)	(377)		(1,222)
Fair Value	281,839	281,839		13,236
Agency-guaranteed residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	439,938	439,938		330,637
Allowance for Credit Losses	0	0		0
Gross Unrealized Gains	4,288	4,288		146
Gross Unrealized Losses	(140)	(140)		(3,745)
Fair Value	444,086	444,086		327,038
Agency-guaranteed residential collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	488,233	488,233		242,858
Allowance for Credit Losses	0	0		0
Gross Unrealized Gains	2,987	2,987		0
Gross Unrealized Losses	(8,606)	(8,606)		(16,112)
Fair Value	482,614	482,614		226,746
Agency-guaranteed commercial collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	96,660	96,660		95,850
Allowance for Credit Losses	0	0		0
Gross Unrealized Gains	540	540		44
Gross Unrealized Losses	(2,411)	(2,411)		(2,819)
Fair Value	94,789	94,789		93,075
Collateralized loan obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	10,809	10,809		257,500
Allowance for Credit Losses	0	0		0
Gross Unrealized Gains	0	0		100
Gross Unrealized Losses	(149)	(149)		(2,193)
Fair Value	10,660	10,660		255,407
Commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost				78,707
Allowance for Credit Losses				0
Gross Unrealized Gains				0
Gross Unrealized Losses				(999)
Fair Value				77,708
Corporate notes
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	344,683	344,683		564,524
Allowance for Credit Losses	(23,868)	(23,868)	$ (16,772)	(7,135)	$ (4,332)	$ (4,972)	$ (3,469)
Gross Unrealized Gains	1,300	1,300		347
Gross Unrealized Losses	(22,683)	(22,683)		(41,406)
Fair Value	299,432	299,432		516,330
Private label collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	383,389	383,389		502,985
Allowance for Credit Losses	0	0		(107)
Gross Unrealized Gains	0	0		95
Gross Unrealized Losses	(16,977)	(16,977)		(27,075)
Fair Value	$ 366,412	$ 366,412		$ 475,898

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