Schedule IV - Mortgage Loan on Real Estate - Mortgage Loan Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Mortgage loans, beginning of period	$ 12,517	$ 0	$ 0
Additions during period:
New mortgage loan	0	12,542	0
Interest income added to principal	0	0	0
Deductions during period:
Paydowns/Repayments	(142)	(25)	0
Mortgage loans, end of period	$ 12,375	$ 12,517	$ 0