SCHEDULE II VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Valuation and qualifying accounts
Balance at beginning of period	$ 2,741	$ 3,321	$ 3,235
(Recovered) charged to costs and expenses	(3)	166	86
Charged to other accounts		(746)
Balance at end of period	$ 2,738	2,741	3,321
Percentage of provision on rent receivables (in percentage)	1.00%
Loan loss reserves
Valuation and qualifying accounts
Balance at beginning of period	$ 2,560	2,447	2,255
(Recovered) charged to costs and expenses	32	113	192
Balance at end of period	2,592	2,560	2,447
Other notes receivable allowance
Valuation and qualifying accounts
Balance at beginning of period	181	128	166
(Recovered) charged to costs and expenses	(35)	53	(38)
Balance at end of period	$ 146	181	128
Straight-line rent receivable allowance
Valuation and qualifying accounts
Balance at beginning of period		746	814
(Recovered) charged to costs and expenses			(68)
Charged to other accounts		$ (746)
Balance at end of period			$ 746