Schedule III (Consolidated) - Real Estate and Accumulated Depreciation - Reconciliation of Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule III, Reconciliation of accumulated depreciation
Balance at beginning of the year	$ 74,256	$ 67,500	$ 71,752
Depreciation expense	8,298	6,756	6,018
Amounts retired or adjusted	(6,594)		(10,270)
Balance at the end of the year	$ 75,960	$ 74,256	$ 67,500