Securitizations and Variable Interest Entities - Summary of Financial Asset and Liabilitiy Involvement with Consolidated VIEs (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Assets	$ 4,640,831	$ 5,562,631
Liabilities	(3,713,074)	(4,586,861)
Consolidated VIEs
Variable Interest Entity [Line Items]
Assets	1,670,067	2,624,459
Liabilities	(1,569,413)	(2,642,862)
Net Assets	100,654	(18,403)
Consolidated VIEs \| Trust Certificates
Variable Interest Entity [Line Items]
Assets	1,226,957	2,624,459
Liabilities	(1,224,473)	(2,642,862)
Net Assets	2,484	$ (18,403)
Consolidated VIEs \| Securitizations
Variable Interest Entity [Line Items]
Assets	375,607
Liabilities	(312,832)
Net Assets	62,775
Consolidated VIEs \| Warehouse Credit Facility
Variable Interest Entity [Line Items]
Assets	67,503
Liabilities	(32,108)
Net Assets	$ 35,395

Variable Interest Entity, Carrying Amount, Assets and Liabilities, Net

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- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(12))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(11))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.

+ 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 210.5-02.19-26)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

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+ References

No definition available.

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