INVESTMENT SECURITIES - Gross Unrealized Losses and Fair Value, Aggregated by Investment Category (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	$ 524,074	$ 618,574
Less than 12 Months, Unrealized Losses	(8,916)	(11,103)
12 Months or More, Fair Value	619,146	974,040
12 Months or More, Unrealized Losses	(48,102)	(56,938)
Total, Fair Value	1,143,220	1,592,614
Total, Unrealized Losses	(57,018)	(68,041)
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	0
Less than 12 Months, Unrealized Losses	0
12 Months or More, Fair Value	3,200
12 Months or More, Unrealized Losses	(216)
Total, Fair Value	3,200
Total, Unrealized Losses	(216)
Agency-guaranteed residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	308,429	266,568
Less than 12 Months, Unrealized Losses	(3,417)	(3,745)
12 Months or More, Fair Value	0	0
12 Months or More, Unrealized Losses	0	0
Total, Fair Value	308,429	266,568
Total, Unrealized Losses	(3,417)	(3,745)
Agency-guaranteed residential collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	115,580	126,602
Less than 12 Months, Unrealized Losses	(1,540)	(2,717)
12 Months or More, Fair Value	96,069	100,144
12 Months or More, Unrealized Losses	(9,848)	(13,395)
Total, Fair Value	211,649	226,746
Total, Unrealized Losses	(11,388)	(16,112)
Agency-guaranteed commercial collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	44,598	85,902
Less than 12 Months, Unrealized Losses	(1,926)	(2,819)
12 Months or More, Fair Value	30,891	0
12 Months or More, Unrealized Losses	(1,419)	0
Total, Fair Value	75,489	85,902
Total, Unrealized Losses	(3,345)	(2,819)
Collateralized loan obligations
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	0	35,710
Less than 12 Months, Unrealized Losses	0	(265)
12 Months or More, Fair Value	10,552	205,639
12 Months or More, Unrealized Losses	(248)	(1,928)
Total, Fair Value	10,552	241,349
Total, Unrealized Losses	(248)	(2,193)
Commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value		0
Less than 12 Months, Unrealized Losses		0
12 Months or More, Fair Value		77,708
12 Months or More, Unrealized Losses		(999)
Total, Fair Value		77,708
Total, Unrealized Losses		(999)
Corporate notes
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	25,766	74,373
Less than 12 Months, Unrealized Losses	(1,734)	(976)
12 Months or More, Fair Value	143,729	239,509
12 Months or More, Unrealized Losses	(9,544)	(16,064)
Total, Fair Value	169,495	313,882
Total, Unrealized Losses	(11,278)	(17,040)
Private label collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	29,701	29,419
Less than 12 Months, Unrealized Losses	(299)	(581)
12 Months or More, Fair Value	334,705	351,040
12 Months or More, Unrealized Losses	(26,827)	(24,552)
Total, Fair Value	364,406	380,459
Total, Unrealized Losses	$ (27,126)	$ (25,133)