Servicing Advance Liabilities - Additional Information (Detail) $ in Thousands		3 Months Ended	9 Months Ended	12 Months Ended
	Oct. 17, 2016 USD ($)	Dec. 31, 2016 USD ($)	Oct. 04, 2016 USD ($)	Dec. 31, 2016 USD ($) Credit_Facility	Oct. 05, 2016 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Short-term Debt [Line Items]
Outstanding borrowings		$ 783,229		$ 783,229			$ 1,229,280
Servicing Advance Facilities [Member]
Short-term Debt [Line Items]
Outstanding borrowings		708,462		708,462			1,072,541
Early Advance Reimbursement Agreement [Member]
Short-term Debt [Line Items]
Outstanding borrowings		74,767		74,767			$ 156,739
Secured Debt [Member]
Short-term Debt [Line Items]
Aggregate borrowing capacity		$ 1,200,000		$ 1,200,000
Weighted-average stated interest rate		3.32%		3.32%			3.25%
Number of facilities without recourse to the Company | Credit_Facility				2
Secured Debt [Member] | Two-year Term Notes [Member]
Short-term Debt [Line Items]
Aggregate borrowing capacity		$ 300,000		$ 300,000		$ 300,000
Fixed Interest Rate		2.68%		2.68%
Expected repayment date				Oct. 15, 2018
Secured Debt [Member] | Three-year Term Notes [Member]
Short-term Debt [Line Items]
Aggregate borrowing capacity		$ 140,000		$ 140,000
Fixed Interest Rate		3.45%		3.45%
Expected repayment date				Oct. 15, 2018
Secured Debt [Member] | All Other Servicing Advance Facilities [Member]
Short-term Debt [Line Items]
Expected repayment date				Jul. 31, 2018
Variable Interest Rate Basis				LIBOR
Secured Debt [Member] | All Other Servicing Advance Facilities [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Short-term Debt [Line Items]
Interest rate spread				2.50%
Secured Debt [Member] | All Other Servicing Advance Facilities [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Short-term Debt [Line Items]
Interest rate spread				3.00%
Secured Debt [Member] | Servicing Advance Facilities [Member]
Short-term Debt [Line Items]
Collateral pledged		$ 800,000		$ 800,000
Secured Debt [Member] | Variable Funding Notes [Member]
Short-term Debt [Line Items]
Aggregate borrowing capacity		$ 400,000	$ 600,000	400,000	$ 400,000
Expected repayment date		Oct. 04, 2017	Oct. 19, 2016
Outstanding borrowings		$ 142,000		142,000
Secured Debt [Member] | One-year Term Notes [Member]
Short-term Debt [Line Items]
Notes previously issued that were redeemed	$ 360,000
Secured Debt [Member] | Term Notes [Member]
Short-term Debt [Line Items]
Outstanding borrowings		440,000		440,000
Secured Debt [Member] | Early Advance Reimbursement Agreement [Member]
Short-term Debt [Line Items]
Aggregate borrowing capacity		$ 200,000		$ 200,000
Expected repayment date				Mar. 31, 2017
Period Following Expiration, Recovered Collections Remitted				18 months