Debt and Preferred Equity Investments - Preferred Equity Investments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Preferred equity investment
Mortgage loans on real estate, interest rate	8.99%
Carrying value	$ 2,099,393	$ 2,114,041
Preferred Equity, April 2021
Preferred equity investment
Future Funding Obligations	0
Senior Financing	272,000
Carrying value	143,183	144,423
Preferred Equity Redeemed in May 2017
Preferred equity investment
Future Funding Obligations	0
Senior Financing	1,768,000
Carrying value	$ 143,274	0
Preferred equity investments
Preferred equity investment
Mortgage loans on real estate, interest rate	9.12%
Future Funding Obligations	$ 0
Senior Financing	2,040,000
Carrying value	$ 286,457	$ 144,423

Loans and Leases Receivable, Funding Obligation

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- Definition

Amount as of the balance sheet date of debt which holds a position senior to the entity's investment in a mortgage loan on real estate.

+ References

No definition available.

+ Details

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- Definition

Interest rate of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column B
-Subsection 29

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column B))
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

+ Details

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- Definition

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.

+ Details

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- Definition

The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(c))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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