Loan Participations Payable, net (Details) $ in Thousands	Mar. 31, 2018 USD ($) loan	Dec. 31, 2017 USD ($) loan
Loan Participations Payable, net [Line Items]
Unamortized discounts and deferred financing costs, net	$ (59,399)	$ (63,591)
Loan participations payable, net	85,354	102,425
Loans receivable, net	$ 1,359,761	$ 1,211,079
Total loan participations payable, net
Loan Participations Payable, net [Line Items]
Number of loan participations payable | loan	2	2
Weighted average interest rate (as a percent)	6.80%	6.50%
Total loan participations payable, net
Loan Participations Payable, net [Line Items]
Loan participations payable, gross	$ 85,621	$ 102,737
Unamortized discounts and deferred financing costs, net	(267)	(312)
Total loan participations payable, net
Loan Participations Payable, net [Line Items]
Loans receivable, net	$ 85,300	$ 102,300