SCHEDULE III - REAL ESTATE AND ACCUMULATED DEPRECIATION - Change in Total Cost of Real Estate Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	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	$ 1,105,504	$ 654,560	$ 423,729	$ 392,463	$ 200,974
Acquisitions	187,032	444,233	222,273	26,979	185,995
Dispositions during the year	0	0	0	(951)	0
Capital expenditures and transfers from construction-in-progress	13,656	6,711	8,558	5,238	5,494
Investment in Real Estate	$ 1,306,192	$ 1,105,504	$ 654,560	$ 423,729	$ 392,463