Schedule IV - Real Estate Mortgage Loans (Mortgage Loan Reconciliation) (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]
Beginning Balance	$ 565,875	$ 634,201	$ 780,509
New Loans	9,900	0	140,000
Construction Draws	0	0	13,402
Total additions	9,900	0	153,402
Principal Repayments	(148,658)	(68,326)	(299,710)
Total deductions	(148,658)	(68,326)	(299,710)
Ending Balance	$ 427,117	$ 565,875	$ 634,201