SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation and qualifying accounts
Balance at beginning of period	$ 3,321	$ 3,235	$ 3,441
(Recovered) charged to costs and expenses	166	86	(206)
Charged to other accounts	(746)
Balance at end of period	$ 2,741	3,321	3,235
Percentage of provision on rent receivables (in percentage)	1.00%
Loan loss reserves
Valuation and qualifying accounts
Balance at beginning of period	$ 2,447	2,255	2,315
(Recovered) charged to costs and expenses	113	192	(60)
Balance at end of period	2,560	2,447	2,255
Other notes receivable allowance
Valuation and qualifying accounts
Balance at beginning of period	128	166	166
(Recovered) charged to costs and expenses	53	(38)
Balance at end of period	181	128	166
Straight-line rent receivable allowance
Valuation and qualifying accounts
Balance at beginning of period	746	814	960
(Recovered) charged to costs and expenses		(68)	(146)
Charged to other accounts	$ (746)
Balance at end of period		$ 746	$ 814