Fair Value - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights at fair value transferred from Level 3 to Level 2	$ 212,630
Real estate owned, net	104,554	$ 77,383
Loans in process of foreclosure	$ 418,400	244,900
Concentrations threshold	5.00%
Real estate owned expenses	$ 6,900	6,300	$ 7,000
Real estate owned, lower of cost or fair value adjustment	5,100	5,500	$ 2,800
Reverse Mortgage [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Real estate owned, net	90,700	66,400
Servicing [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Real estate owned, net	12,900	10,400
Other Non-Reportable Segment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Real estate owned, net	1,000	600
Servicing Rights Carried at Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights at fair value transferred from Level 3 to Level 2	212,630
Mortgage Loans Related To Non Residual Trusts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights at fair value transferred from Level 3 to Level 2	$ 0
Number of days delinquent	90 days
Loans 90 days or more past due, fair value	$ 1,600	2,600
Loans 90 days or more past due, unpaid principal balance	$ 29,500	$ 16,200
Mortgage Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of days delinquent	90 days
Charged-off Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing rights at fair value transferred from Level 3 to Level 2	$ 0
Number of days delinquent	90 days