DISCLOSURES ABOUT FAIR VALUE OF FINANCIAL INSTRUMENTS - Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring and Nonrecurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets
Fair Value	$ 2,377,733	$ 2,376,860
Fair Value, Measurements, Recurring
Assets
Assets, fair value	3,863,313	3,481,980
Fair Value, Measurements, Nonrecurring
Assets
Assets, fair value	18,003	2,373
Asset-backed securities
Assets
Fair Value	37,670	92,629
Asset-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	37,670	92,629
Agency-guaranteed residential mortgage-backed securities
Assets
Fair Value	221,178
Agency-guaranteed residential mortgage-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	221,178
Agency-guaranteed residential collateralized mortgage obligations
Assets
Fair Value	194,873	116,908
Agency-guaranteed residential collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	194,873	116,908
Agency-guaranteed commercial collateralized mortgage obligations
Assets
Fair Value	96,943
Agency-guaranteed commercial collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	96,943
Collateralized loan obligations
Assets
Fair Value	310,429	489,092
Collateralized loan obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	310,429	489,092
Commercial mortgage-backed securities
Assets
Fair Value	77,074	121,636
Commercial mortgage-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	77,074	121,636
Corporate notes
Assets
Fair Value	594,971	583,034
Corporate notes | Fair Value, Measurements, Recurring
Assets
Fair Value	594,971	583,034
Private label collateralized mortgage obligations
Assets
Fair Value	844,595	973,561
Private label collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	844,595	973,561
Derivatives | Fair Value, Measurements, Recurring
Assets
Assets, fair value	15,546	17,931
Loans held for sale – fair value option | Fair Value, Measurements, Recurring
Assets
Assets, fair value	219,621	189,277
Loans receivable, mortgage finance – fair value option | Fair Value, Measurements, Recurring
Assets
Assets, fair value	1,250,413	897,912
Derivatives  | Fair Value, Measurements, Recurring
Liabilities
Financial liabilities, fair value	21,486	27,110
Collateral-dependent loans | Fair Value, Measurements, Nonrecurring
Assets
Assets, fair value	18,003	2,373
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Assets
Assets, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Nonrecurring
Assets
Assets, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Asset-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Agency-guaranteed residential mortgage-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Agency-guaranteed residential collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Agency-guaranteed commercial collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Collateralized loan obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial mortgage-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate notes | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Private label collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivatives | Fair Value, Measurements, Recurring
Assets
Assets, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Loans held for sale – fair value option | Fair Value, Measurements, Recurring
Assets
Assets, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Loans receivable, mortgage finance – fair value option | Fair Value, Measurements, Recurring
Assets
Assets, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivatives  | Fair Value, Measurements, Recurring
Liabilities
Financial liabilities, fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Collateral-dependent loans | Fair Value, Measurements, Nonrecurring
Assets
Assets, fair value	0	0
Significant Other Observable Inputs (Level 2)
Assets
Fair Value	2,360,908	2,341,911
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets
Assets, fair value	3,629,318	3,258,944
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Nonrecurring
Assets
Assets, fair value	0	0
Significant Other Observable Inputs (Level 2) | Asset-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	20,845	57,680
Significant Other Observable Inputs (Level 2) | Agency-guaranteed residential mortgage-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	221,178
Significant Other Observable Inputs (Level 2) | Agency-guaranteed residential collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	194,873	116,908
Significant Other Observable Inputs (Level 2) | Agency-guaranteed commercial collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	96,943
Significant Other Observable Inputs (Level 2) | Collateralized loan obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	310,429	489,092
Significant Other Observable Inputs (Level 2) | Commercial mortgage-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	77,074	121,636
Significant Other Observable Inputs (Level 2) | Corporate notes | Fair Value, Measurements, Recurring
Assets
Fair Value	594,971	583,034
Significant Other Observable Inputs (Level 2) | Private label collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	844,595	973,561
Significant Other Observable Inputs (Level 2) | Derivatives | Fair Value, Measurements, Recurring
Assets
Assets, fair value	15,474	17,906
Significant Other Observable Inputs (Level 2) | Loans held for sale – fair value option | Fair Value, Measurements, Recurring
Assets
Assets, fair value	2,523	1,215
Significant Other Observable Inputs (Level 2) | Loans receivable, mortgage finance – fair value option | Fair Value, Measurements, Recurring
Assets
Assets, fair value	1,250,413	897,912
Significant Other Observable Inputs (Level 2) | Derivatives  | Fair Value, Measurements, Recurring
Liabilities
Financial liabilities, fair value	21,486	27,110
Significant Other Observable Inputs (Level 2) | Collateral-dependent loans | Fair Value, Measurements, Nonrecurring
Assets
Assets, fair value	0	0
Significant Unobservable Inputs (Level 3)
Assets
Fair Value	16,825	34,949
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets
Assets, fair value	233,995	223,036
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Nonrecurring
Assets
Assets, fair value	18,003	2,373
Significant Unobservable Inputs (Level 3) | Asset-backed securities
Assets
Fair Value	16,825	34,949
Significant Unobservable Inputs (Level 3) | Asset-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	16,825	34,949
Significant Unobservable Inputs (Level 3) | Agency-guaranteed residential mortgage-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	0
Significant Unobservable Inputs (Level 3) | Agency-guaranteed residential collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Agency-guaranteed commercial collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	0
Significant Unobservable Inputs (Level 3) | Collateralized loan obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Commercial mortgage-backed securities | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Corporate notes | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Private label collateralized mortgage obligations | Fair Value, Measurements, Recurring
Assets
Fair Value	0	0
Significant Unobservable Inputs (Level 3) | Derivatives | Fair Value, Measurements, Recurring
Assets
Assets, fair value	72	25
Significant Unobservable Inputs (Level 3) | Loans held for sale – fair value option | Fair Value, Measurements, Recurring
Assets
Assets, fair value	217,098	188,062
Significant Unobservable Inputs (Level 3) | Loans receivable, mortgage finance – fair value option | Fair Value, Measurements, Recurring
Assets
Assets, fair value	0	0
Significant Unobservable Inputs (Level 3) | Derivatives  | Fair Value, Measurements, Recurring
Liabilities
Financial liabilities, fair value	0	0
Significant Unobservable Inputs (Level 3) | Collateral-dependent loans | Fair Value, Measurements, Nonrecurring
Assets
Assets, fair value	$ 18,003	$ 2,373