Related Party Transactions and Investments in Non-Consolidated Entities - Management fees and interest income from loans (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Schedule of Equity Method Investments [Line Items]
Asset management fees, low end of range (as a percent)	1.00%
Asset management fees, high end of range (as a percent)	5.00%
Notice period for cancellation of applicable contracts	30 days
Revenue, Product and Service [Extensible List]	Asset management fees	Asset management fees
Asset management fees
Schedule of Equity Method Investments [Line Items]
Revenue	$ 34,000	$ 45,000
Sponsored REITs
Schedule of Equity Method Investments [Line Items]
Impairment of Sponsored REIT	$ 0