SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Prior Liens				$ 0
Principal Balance	$ 23,146	$ 16,033	$ 16,033	21,468
Book Value				21,487
Aggregate cost for federal income tax purposes				21,600
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Balance at the beginning of the year	23,146	16,033	39,026
Additions during period:
Draws	1,689	10,943	1,738
New mortgage loans	0	0	12,987
Interest income added to principal	194	1,528	539
Deductions during period:
Paydowns/repayments	(3,561)	(5,358)	(14,570)
Conversion to real property	0	0	(19,085)
Write-offs	0	0	(4,602)
Balance at the end of the year	$ 21,468	$ 23,146	$ 16,033
Mortgages | River Vista
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Contractual Interest Rate	10.00%
Prior Liens				0
Principal Balance	$ 19,000			19,000
Book Value				19,000
Deductions during period:
Balance at the end of the year	$ 19,000
Construction Mortgages | Arlington
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Contractual Interest Rate	8.00%
Prior Liens				0
Principal Balance	$ 2,468			2,468
Book Value				$ 2,487
Deductions during period:
Balance at the end of the year	$ 2,468