NON-CONSOLIDATED VARIABLE INTEREST ENTITIES AND SERVICING ASSETS - Key Economic Assumptions Used in Determining Fair Value at Time of Sale of Loans (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Government Guaranteed Mortgage Loans [Member] | Maximum [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	7.60%	9.20%	9.60%
Discount rate	12.00%	11.50%	11.50%
Government Guaranteed Mortgage Loans [Member] | Minimum [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	5.90%	7.80%	9.10%
Discount rate	11.50%	11.50%	11.50%
Conventional Loan [Member] | Maximum [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	8.00%	9.00%	9.40%
Discount rate	10.00%	9.50%	9.50%
Conventional Loan [Member] | Minimum [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	6.30%	7.90%	8.90%
Discount rate	9.50%	9.50%	9.50%
Conventional Non Conforming Mortgage Loans [Member] | Maximum [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	14.10%	14.40%	14.00%
Discount rate	14.30%	13.80%	13.90%
Conventional Non Conforming Mortgage Loans [Member] | Minimum [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	9.30%	12.90%	12.70%
Discount rate	13.80%	13.80%	13.80%