SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE - Loans On Real Estate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Mortgage Loans on Real Estate [Line Items]
Face Amount of Notes Receivable	$ 215,200
Net carrying amount of notes receivable	$ 109,613	$ 153,829	$ 276,163	$ 147,188
First Mortgage Loan, 6.0% Loan, Due 4/30/2020
Mortgage Loans on Real Estate [Line Items]
Effective Interest Rate	6.00%
Face Amount of Notes Receivable	$ 15,000
Net carrying amount of notes receivable	$ 17,802
First Mortgage Loan, 8.1% Loan, Due 4/30/2019
Mortgage Loans on Real Estate [Line Items]
Effective Interest Rate	8.10%
Face Amount of Notes Receivable	$ 153,400
Net carrying amount of notes receivable	$ 38,673
Zero Coupon Loan Due 5/31/2020
Mortgage Loans on Real Estate [Line Items]
Effective Interest Rate	2.50%
Face Amount of Notes Receivable	$ 29,793
Net carrying amount of notes receivable	$ 32,582
Mezzanine Loan 18.0% Loan Due 7/1/2020
Mortgage Loans on Real Estate [Line Items]
Effective Interest Rate	18.00%
Face Amount of Notes Receivable	$ 3,007
Net carrying amount of notes receivable	$ 5,306
Preferred Equity, 15.3% Loan, Due 2/3/2021
Mortgage Loans on Real Estate [Line Items]
Effective Interest Rate	15.30%
Face Amount of Notes Receivable	$ 14,000
Net carrying amount of notes receivable	$ 15,250