Real Estate Securities - Components of Carrying Value (Which Equals Fair Value) of Residential Available for Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Carrying Value	$ 572,752	$ 829,245
Senior Securities
Schedule of Available-for-sale Securities [Line Items]
Carrying Value	136,546	279,251
Senior Securities \| Prime
Schedule of Available-for-sale Securities [Line Items]
Carrying Value	128,843	210,993
Senior Securities \| Non-prime
Schedule of Available-for-sale Securities [Line Items]
Carrying Value	7,703	68,258
Re-REMIC
Schedule of Available-for-sale Securities [Line Items]
Carrying Value	85,479	165,064
Subordinate Securities
Schedule of Available-for-sale Securities [Line Items]
Carrying Value	350,727	384,930
Residential
Schedule of Available-for-sale Securities [Line Items]
Principal balance	700,829	973,227
Credit reserve	(47,473)	(48,869)
Unamortized discount, net	(198,112)	(237,107)
Amortized cost	455,244	687,251
Gross unrealized gains	120,677	147,001
Gross unrealized losses	(3,169)	(5,007)
Carrying Value	572,752	829,245
Residential \| Senior Securities \| Prime
Schedule of Available-for-sale Securities [Line Items]
Principal balance	139,736	217,605
Credit reserve	(4,174)	(1,305)
Unamortized discount, net	(40,379)	(22,079)
Amortized cost	95,183	194,221
Gross unrealized gains	35,589	20,263
Gross unrealized losses	(1,929)	(3,491)
Carrying Value	128,843	210,993
Residential \| Senior Securities \| Non-prime
Schedule of Available-for-sale Securities [Line Items]
Principal balance	9,126	75,591
Credit reserve	(640)	(5,101)
Unamortized discount, net	(1,498)	(8,395)
Amortized cost	6,988	62,095
Gross unrealized gains	715	6,249
Gross unrealized losses	0	(86)
Carrying Value	7,703	68,258
Residential \| Re-REMIC
Schedule of Available-for-sale Securities [Line Items]
Principal balance	95,608	189,782
Credit reserve	(6,857)	(10,332)
Unamortized discount, net	(19,613)	(71,670)
Amortized cost	69,138	107,780
Gross unrealized gains	16,341	57,284
Gross unrealized losses	0	0
Carrying Value	85,479	165,064
Residential \| Subordinate Securities
Schedule of Available-for-sale Securities [Line Items]
Principal balance	456,359	490,249
Credit reserve	(35,802)	(32,131)
Unamortized discount, net	(136,622)	(134,963)
Amortized cost	283,935	323,155
Gross unrealized gains	68,032	63,205
Gross unrealized losses	(1,240)	(1,430)
Carrying Value	$ 350,727	$ 384,930

Balance of credit reserve on available-for-sale securities.

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Available For Sale Securities Principal Balance

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Balance of net unamortized discount on available-for-sale securities.

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- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

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-Publisher FASB
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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ 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 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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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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