SCHEDULE IV MORTGAGE LOANS ON REAL ESTATE - Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Mortgage loans on real estate
Balance at the beginning of the period	$ 242,939	$ 223,907	$ 229,801
New mortgage loans	7,500	14,525
Other additions	4,842	6,839	11,913
Amortization of mortgage premium	(4)	(4)	(4)
Collections of principal	(1,065)	(2,136)	(17,863)
Loan loss reserve	(113)	(192)	60
Balance at the end of the period	$ 254,099	$ 242,939	$ 223,907