Loans Receivable - Schedule of Loans Receivable (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Loans Receivable:
Mezzanine	$ 25,702	$ 21,013
Participating development loans and other	111,942	42,037
Unamortized discounts, fees and costs	(25)	(52)
Loans receivable, net	137,619	62,998
Remaining loans receivable commitments	17,000
Loans receivable commitments	115,000
Real Estate Secured
Loans Receivable:
Mezzanine	0	0
Participating development loans and other	111,942	42,037
Unamortized discounts, fees and costs	0	0
Loans receivable, net	111,942	42,037
Other Secured
Loans Receivable:
Mezzanine	25,702	21,013
Participating development loans and other	0	0
Unamortized discounts, fees and costs	(25)	(52)
Loans receivable, net	$ 25,677	$ 20,961