Fair Value - Schedule of Carrying Amounts and Estimated Fair Values of Financial Assets and Liabilities Not Recorded at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financial assets
Residential loans at amortized cost, net	$ 678,482	$ 665,209
Servicer and protective advances, net	1,005,157	1,195,380
Financial liabilities
Mortgage-backed debt carried at amortized cost	916,952	943,956
Level 3 \| Carrying Amount Measurement
Financial assets
Residential loans at amortized cost, net	678,482	665,209
Servicer and protective advances, net	1,005,157	1,195,380
Financial liabilities
Servicing advance liabilities	661,057	781,734
Mortgage-backed debt carried at amortized cost	418,184	429,931
Level 3 \| Estimated Fair Value Measurement
Financial assets
Residential loans at amortized cost, net	693,028	674,851
Servicer and protective advances, net	948,453	1,147,155
Financial liabilities
Servicing advance liabilities	661,646	782,570
Mortgage-backed debt carried at amortized cost	428,272	435,679
Level 2 \| Carrying Amount Measurement
Financial liabilities
Corporate debt	2,109,865	2,126,176
Level 2 \| Estimated Fair Value Measurement
Financial liabilities
Corporate debt	$ 1,612,373	$ 1,967,518

Obligation reflecting another party's right to economic interests in another entity or trust under a contractual right. For example, an investor may purchase a beneficial interest in a securitization transaction.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount of collateralized debt obligations classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822

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Carrying amount of advances for servicer advances (mortgage payments) and protective advances (property taxes and insurance) made by the Company on behalf of the borrower to protect the Company's investment in residential loans and real estate owned, net of allowance for uncollectible advances.

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