NON-CONSOLIDATED VARIABLE INTEREST ENTITIES AND SERVICING ASSETS - Key Economic Assumptions Used in Determining Fair Value at Time of Sale of Loans (Detail)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Weighted Average [Member] | Conventional Loan [Member]
Assumption For Fair Value On Securitization Date Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Line Items]
Constant prepayment rate	7.70%	6.60%
Discount rate	9.50%	10.00%
Weighted Average [Member] | Conventional Non Conforming Mortgage Loans [Member]
Assumption For Fair Value On Securitization Date Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Line Items]
Constant prepayment rate	5.70%	6.60%
Discount rate	12.80%	12.30%
Weighted Average [Member] | Government-guaranteed mortgage loans [Member]
Assumption For Fair Value On Securitization Date Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Line Items]
Constant prepayment rate	6.70%	6.70%
Discount rate	11.50%	12.00%
Maximum [Member] | Conventional Loan [Member]
Assumption For Fair Value On Securitization Date Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Line Items]
Constant prepayment rate	16.00%	18.40%
Discount rate	9.50%	10.00%
Maximum [Member] | Conventional Non Conforming Mortgage Loans [Member]
Assumption For Fair Value On Securitization Date Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Line Items]
Constant prepayment rate	7.00%	21.90%
Discount rate	14.00%	14.50%
Maximum [Member] | Government-guaranteed mortgage loans [Member]
Assumption For Fair Value On Securitization Date Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Line Items]
Constant prepayment rate	11.60%	18.30%
Discount rate	11.50%	12.00%
Minimum [Member] | Conventional Loan [Member]
Assumption For Fair Value On Securitization Date Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Line Items]
Constant prepayment rate	3.80%	3.40%
Discount rate	9.50%	10.00%
Minimum [Member] | Conventional Non Conforming Mortgage Loans [Member]
Assumption For Fair Value On Securitization Date Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Line Items]
Constant prepayment rate	2.10%	4.90%
Discount rate	11.50%	12.00%
Minimum [Member] | Government-guaranteed mortgage loans [Member]
Assumption For Fair Value On Securitization Date Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities [Line Items]
Constant prepayment rate	4.80%	4.80%
Discount rate	11.50%	12.00%