Schedule III (Consolidated) - Real Estate and Accumulated Depreciation - Reconciliation of Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SEC Schedule III, Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance at beginning of the year	$ 67,349	$ 64,069	$ 58,132
Depreciation expense	6,245	6,002	6,204
Amounts retired or adjusted	(1,842)	(2,722)	(267)
Balance at the end of the year	$ 71,752	$ 67,349	$ 64,069