Payables and Accrued Liabilities - Schedule of Payables and Accrued Liabilities (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Loans subject to repurchase from Ginnie Mae	$ 248,596	$ 184,289
Accounts payable and accrued liabilities	129,291	155,556
Curtailment liability	120,043	121,305
Originations liability	44,020	62,969
Employee-related liabilities	51,741	91,063
Accrued interest payable	9,625	9,414
Servicing rights and related advance purchases payable	15,341	18,187
Derivative instruments	5,924	11,804
Uncertain tax positions	7,015	9,414
Payables to insurance carriers	3,355	5,452
Margin payable on derivative instruments	2,387	30,941
Other	64,052	58,617
Total payables and accrued liabilities	$ 701,390	759,011
Delinquency threshold	90 days
Uncertain tax position related to insurance business sale		$ 2,500