Variable Interest Entities - Summary of Carrying Amounts of Assets and Liabilities of Consolidated VIEs (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Restricted cash and cash equivalents	$ 204,463	$ 708,099
Residential loans at amortized cost, net	665,209	541,406
Residential loans at fair value	12,416,542	12,673,439
Receivables, net	267,962	137,190
Servicer and protective advances, net	1,195,380	1,631,065
Other assets	242,290	200,364
Total assets	16,758,896	18,549,447
Liabilities
Payables and accrued liabilities	759,011	597,926
Servicing advance liabilities	783,229	1,229,280
Mortgage-backed debt	943,956	1,051,679
Total liabilities	16,478,636	17,744,771
Variable Interest Entity, Primary Beneficiary [Member]
ASSETS
Restricted cash and cash equivalents	45,843	59,705
Residential loans at amortized cost, net	462,877	500,563
Residential loans at fair value	492,499	526,016
Receivables, net	15,798	16,542
Servicer and protective advances, net	734,707	1,136,246
Other assets	19,831	12,170
Total assets	1,771,555	2,251,242
Liabilities
Payables and accrued liabilities	2,985	3,435
Servicing advance liabilities	650,565	992,769
Mortgage-backed debt	943,956	1,051,679
Total liabilities	1,597,506	2,047,883
Variable Interest Entity, Primary Beneficiary [Member] | Residual Trusts [Member]
ASSETS
Restricted cash and cash equivalents	13,321	13,369
Residential loans at amortized cost, net	462,877	500,563
Residential loans at fair value	0	0
Receivables, net	0	0
Servicer and protective advances, net	0	0
Other assets	10,028	9,357
Total assets	486,226	523,289
Liabilities
Payables and accrued liabilities	2,140	2,084
Servicing advance liabilities	0	0
Mortgage-backed debt	429,931	469,339
Total liabilities	432,071	471,423
Variable Interest Entity, Primary Beneficiary [Member] | Non-Residual Trusts [Member]
ASSETS
Restricted cash and cash equivalents	10,257	11,388
Residential loans at amortized cost, net	0	0
Residential loans at fair value	450,377	526,016
Receivables, net	15,033	16,542
Servicer and protective advances, net	0	0
Other assets	1,028	558
Total assets	476,695	554,504
Liabilities
Payables and accrued liabilities	0	0
Servicing advance liabilities	0	0
Mortgage-backed debt	514,025	582,340
Total liabilities	514,025	582,340
Variable Interest Entity, Primary Beneficiary [Member] | Servicer and Protective Advance Financing VIEs [Member]
ASSETS
Restricted cash and cash equivalents	22,265	34,948
Residential loans at amortized cost, net	0	0
Residential loans at fair value	0	0
Receivables, net	0	0
Servicer and protective advances, net	734,707	1,136,246
Other assets	1,440	2,255
Total assets	758,412	1,173,449
Liabilities
Payables and accrued liabilities	845	1,351
Servicing advance liabilities	650,565	992,769
Mortgage-backed debt	0	0
Total liabilities	651,410	$ 994,120
Variable Interest Entity, Primary Beneficiary [Member] | Revolving Credit Facilities Related VIEs [Member]
ASSETS
Restricted cash and cash equivalents	0
Residential loans at amortized cost, net	0
Residential loans at fair value	42,122
Receivables, net	765
Servicer and protective advances, net	0
Other assets	7,335
Total assets	50,222
Liabilities
Payables and accrued liabilities	0
Servicing advance liabilities	0
Mortgage-backed debt	0
Total liabilities	$ 0