Fair Value - Schedule of Estimated Fair Value and Unpaid Principal Balance of Loans and Debt Instruments under the Fair Value Option (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Option, Quantitative Disclosures [Line Items]
Residential loans at fair value	$ 9,146,956	$ 10,725,232
Total loans at fair value under the fair value option	9,146,956	10,725,232
Total loans at fair value under the fair value option, unpaid principal balance	11,111,043	12,706,349
Mortgage-backed debt related to Non-Residual Trusts	131,313	348,682
Mortgage-backed debt related to Non-Residual Trusts, unpaid principal balance	139,064	353,262
HMBS related obligations at fair value	7,264,821	9,175,128
HMBS related obligations at fair value, unpaid principal balance	6,987,306	8,743,700
Total debt instruments at fair value under the fair value option	7,396,134	9,523,810
Total debt instruments at fair value under the fair value option, unpaid principal balance	7,126,370	9,096,962
Reverse Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Residential loans at fair value	8,202,775	9,789,444
Residential loans at fair value, unpaid principal balance	8,030,431	9,460,616
Mortgage Loans Held for Sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Residential loans at fair value	777,287	588,553
Residential loans at fair value, unpaid principal balance	746,229	567,492
Mortgage Loans Related To Non-Residual Trusts [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Residential loans at fair value	117,410	301,435
Residential loans at fair value, unpaid principal balance	130,840	344,421
Mortgage Loans Related To Residual Trusts and Other Loans Held for Investment [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Residential loans at fair value	1,044	0
Residential loans at fair value, unpaid principal balance	1,052	0
Charged-off Loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Residential loans at fair value	48,440	45,800
Residential loans at fair value, unpaid principal balance	$ 2,202,491	$ 2,333,820

Beneficial Interest, Non-Residual Trusts At Fair Value

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Beneficial Interest, Non-Residual Trusts At Fair Value Unpaid Principal Balance

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Fair value option assets fair value balance.

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Fair value option unpaid principal asset balance.

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Fair value option liabilities fair value balance.

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Fair value option unpaid principal liability balance.

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Liability related to the transfer of home equity conversion mortgage backed security related obligations, which is accounted for as a secured borrowing.

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Home equity conversion mortgage backed security related obligations unpaid principal balance.

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Loans receivable at fair value unpaid principal balance.

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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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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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