Residential Whole Loans (Carrying Value) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Contractually required principal and interest	$ 154,911	$ 185,234	$ 154,911	$ 185,234
Contractual cash flows not expected to be collected (non-accretable yield)	(15,378)	(33,448)	(15,378)	(33,448)
Expected cash flows to be collected	139,533	151,786	139,533	151,786
Interest component of expected cash flows (accretable yield)	(41,947)	(53,916)	(41,947)	(53,916)
Fair value at the date of acquisition	97,586	97,870	97,586	97,870
Purchase credit impaired loans transaction closed in current period which were purchased in prior periods	$ 54,900	$ 97,900	$ 54,900	$ 97,900

Purchase Credit Impaired Loans, Purchase Transaction Committed In Previous Period, Closed in Subsequent Period

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- Definition

Amount of additions to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82894507&loc=d3e13503-111538

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-SubTopic 30
-Section 50
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-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=82894903&loc=d3e15032-111544

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- Definition

Amount of increase of reclassification from nonaccretable difference to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

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- Definition

Amount of cash flows expected to be collected at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
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- Definition

Fair value at acquisition of acquired consumer loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
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- Definition

Amount of contractually required payments receivable at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

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- References

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