SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION - Change in Total Cost of Real Estate Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
SEC Schedule III, Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance at the beginning of the year	$ 1,306,192	$ 1,105,504	$ 654,560	$ 423,729	$ 392,463	$ 200,974
Acquisitions	0	187,032	444,233	222,273	26,979	185,995
Dispositions during the year	0	0	0	0	(951)	0
Capital expenditures and transfers from construction-in-progress	14,081	13,656	6,711	8,558	5,238	5,494
Investment in Real Estate	$ 1,320,273	$ 1,306,192	$ 1,105,504	$ 654,560	$ 423,729	$ 392,463