Segments - Reconciliation of Net Operating Income to Net Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting [Abstract]
Net operating income	$ 11,883	$ 10,731	$ 34,218	$ 30,558
Depreciation and amortization	(4,567)	(3,933)	(12,593)	(11,112)
General and administrative expenses	(1,741)	(1,638)	(5,768)	(5,212)
Acquisition, development and other pursuit costs	(174)		(174)
Impairment charges	(15)		(15)	(533)
Interest expense	(2,734)	(2,598)	(7,977)	(9,802)
Loss on extinguishment of debt		(1,127)		(2,252)
Gain on acquisitions				9,460
Other income (loss)	59	(109)	(23)	343
Income tax benefit (provision)	43	(74)	(135)	137
Net income	$ 2,754	$ 1,252	$ 7,533	$ 11,587