Investments in Real Estate Entities - Expensed Acquisition, Development and Other Pursuit Costs and Impairment of Long-Lived Assets & Casualty Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Other than Temporary Impairment Losses, Investments	$ 0	$ 0

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 8A
-URI http://asc.fasb.org/extlink&oid=121553693&loc=SL6284422-111562

Name:	us-gaap_ImpairmentOfInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration