Real Estate Investments - Mortgage Loans Activity (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Mortgage Loans
Originations and fundings under mortgage loans receivable	$ 2,557	$ 9,736
Scheduled principal payments received	(565)	(565)
Mortgage loan premium amortization	(2)	(2)
Provision for loan loss reserve	(20)	(92)
Net increase in mortgage loans receivable	$ 1,970	$ 9,077