Real Estate Securities - Components of Carrying Value (Which Equals Fair Value) of Residential Available for Sale Securities (Details) - Residential - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Principal balance	$ 465,084	$ 608,145
Credit reserve	(41,074)	(46,549)
Unamortized discount, net	(160,799)	(183,753)
Amortized cost	263,211	377,843
Gross unrealized gains	99,865	131,190
Gross unrealized losses	(1,235)	(1,367)
Carrying Value	361,841	507,666
Senior IO Securities
Debt Securities, Available-for-sale [Line Items]
Principal balance	119,254	189,125
Credit reserve	(7,919)	(8,756)
Unamortized discount, net	(25,173)	(44,041)
Amortized cost	86,162	136,328
Gross unrealized gains	29,134	44,771
Gross unrealized losses	(668)	(1,235)
Carrying Value	114,628	179,864
Mezzanine
Debt Securities, Available-for-sale [Line Items]
Principal balance	37,385	91,471
Credit reserve	0	0
Unamortized discount, net	(3,843)	(9,407)
Amortized cost	33,542	82,064
Gross unrealized gains	2,835	9,938
Gross unrealized losses	0	0
Carrying Value	36,377	92,002
Subordinate Securities
Debt Securities, Available-for-sale [Line Items]
Principal balance	308,445	327,549
Credit reserve	(33,155)	(37,793)
Unamortized discount, net	(131,783)	(130,305)
Amortized cost	143,507	159,451
Gross unrealized gains	67,896	76,481
Gross unrealized losses	(567)	(132)
Carrying Value	$ 210,836	$ 235,800

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

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- Definition

Available For Sale Securities Principal Balance

+ References

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- Definition

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

+ References

No definition available.

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- Definition

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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- Definition

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 45
-Paragraph 1
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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.

+ References

No definition available.

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