Schedule II - Valuation and Qualifying Accounts - Allowances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Notes receivable, valuation allowance	$ 700
Notes receivable, valuation allowance	3,600	$ 2,900
Uncollectible tenant receivables [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period (1)	4,639	2,309	$ 1,712
Balance at Beginning of Period (1)	512
Charged to Costs and Expenses	907	2,604	1,517
Recoveries (Deductions)	(248)	(274)	(920)
Balance at End of Period	1,171	4,639	2,309
Balance at End of Period		512
Allowance for deferred rent [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period (1)	3,339	3,238	1,524
Balance at Beginning of Period (1)	195
Charged to Costs and Expenses	1,357	165	1,752
Recoveries (Deductions)	0	(64)	(38)
Balance at End of Period	$ 1,552	3,339	$ 3,238
Balance at End of Period		$ 195