Residential Loans at Amortized Cost, Net - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Minimum period after which residential loans are placed on non-accrual status	90 days
Minimum duration for past due residential loans to be considered non-performing	30 days
Recorded investment in loans 30 days or more past due	$ 74.4	$ 68.3
Percentage threshold for state concentrations of residential loans	5.00%

Concentrations threshold for state concentrations of residential loans.

No definition available.

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- Definition

Minimum duration for past due residential loans to be considered as non-performing.

+ References

No definition available.

+ Details

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- Definition

Minimum period after which residential loans are placed on nonaccrual status.

+ References

No definition available.

+ Details

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- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524

+ Details

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Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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