Schedule III (Consolidated) - Real Estate and Accumulated Depreciation - Reconciliation of Real Estate Owned (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
SEC Schedule III, Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance at beginning of the year	$ 379,944	$ 436,264	$ 418,197
Amounts capitalized	13,372	26,047	44,795
Impairments	0	0	(5,080)
Cost of real estate sold	(14,584)	(76,060)	(22,022)
Amounts retired or adjusted	(1,064)	(6,307)	374
Balance at the end of the year	$ 377,668	$ 379,944	$ 436,264