Borrowings - Schedule of repurchase and loan agreements (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016	Mar. 22, 2013
Debt Instrument [Line Items]
Amount Outstanding	$ 1,100,106,000	$ 1,220,972,000
Repurchase agreements \| CS Repurchase Agreement due November 17, 2017
Debt Instrument [Line Items]
Maximum borrowing capacity		600,000,000
Book Value of Collateral	372,667,000	902,339,000
Amount Outstanding, before debt issuance costs		582,659,000
Amount of Available Funding	106,757,000	17,341,000
Loan agreement \| Nomura Loan Agreement due April 5, 2018
Debt Instrument [Line Items]
Maximum borrowing capacity	250,000,000	250,000,000
Book Value of Collateral	173,515,000	238,142,000
Amount Outstanding, before debt issuance costs	105,289,000	155,054,000
Amount of Available Funding	144,711,000	94,946,000
Loan agreement \| MSR Loan Agreement due November 9, 2018
Debt Instrument [Line Items]
Maximum borrowing capacity	489,259,000	489,259,000
Book Value of Collateral	625,985,000	638,799,000
Amount Outstanding, before debt issuance costs	489,259,000	489,259,000
Amount of Available Funding	0	0
Loan agreement \| HOME II Loan Agreement due October 9, 2019
Debt Instrument [Line Items]
Maximum borrowing capacity	79,879,000
Book Value of Collateral	104,073,000
Amount Outstanding, before debt issuance costs	79,879,000
Amount of Available Funding	0
Loan agreement \| Term Loan Agreement due April 6, 2022
Debt Instrument [Line Items]
Maximum borrowing capacity	100,000,000
Book Value of Collateral	115,364,000
Amount Outstanding, before debt issuance costs	100,000,000
Amount of Available Funding	0
Loan agreement \| HOME III Loan Agreement due October 9, 2019
Debt Instrument [Line Items]
Maximum borrowing capacity	87,803,000
Book Value of Collateral	115,490,000
Amount Outstanding, before debt issuance costs	87,803,000
Amount of Available Funding	0
Repurchase and loan agreements
Debt Instrument [Line Items]
Maximum borrowing capacity	1,356,941,000	1,339,259,000
Book Value of Collateral	1,507,094,000	1,779,280,000
Deferred debt issuance costs	(5,367,000)	(6,000,000)
Amount Outstanding	1,100,106,000	1,220,972,000
Amount of Available Funding	251,468,000	112,287,000
Repurchase agreements \| CS Repurchase Agreement due November 17, 2017
Debt Instrument [Line Items]
Maximum borrowing capacity	350,000,000	$ 600,000,000.0	$ 100,000,000.0
Amount Outstanding, before debt issuance costs	$ 243,243,000

Secured Debt, Repurchase Agreements And Loan Agreements

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- Definition

Secured Debt, Repurchase Agreements And Loan Agreements, Before Deducting Debt Issuance Costs

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5086-111524

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