Payables and Accrued Liabilities - Schedule of Payables and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Loans subject to repurchase from Ginnie Mae	$ 466,452	$ 542,398
Accounts payable and accrued liabilities	109,696	129,731
Curtailment liability	99,781	140,905
Employee-related liabilities	45,480	52,097
Loan repurchase obligation	29,360	31,704
Originations liability	28,240	25,613
Accrued interest payable	18,833	33,322
Derivative instruments	13,737	1,250
Servicing rights and related advance purchases payable	12,615	14,923
Uncertain tax positions	3,660	5,601
Other	40,168	42,756
Subtotal	868,022	1,020,300
Less: Liabilities subject to compromise	0	25,807
Total payables and accrued liabilities	$ 868,022	$ 994,493