Schedule III - Changes in Accumulated Depreciation Including Real Estate Assets Held for Sale (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Balance at beginning of period	$ 144,235	$ 114,399	$ 93,430
Depreciation	46,935	33,349	31,026
Depreciation on disposed property	(9,213)	(3,513)	(10,057)
Other	(516)
Balance at end of period	$ 181,441	$ 144,235	$ 114,399