Quarterly Results (Unaudited) - Schedule of Quarterly Income Statement Including Basic and Diluted Earning Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Total revenues from continuing operations	$ 220,694	$ 180,241	$ 219,099	$ 184,334	$ 185,387	$ 162,631	$ 182,987	$ 158,924	$ 804,368	$ 689,929	$ 634,835
Operating income from continuing operations	23,721	2,800	26,887	11,980	11,803	2,422	18,740	8,079	65,388	41,044	59,554
Net (loss) income	$ 6,863	$ (6,257)	$ (1,445)	$ 391	$ (2,243)	$ (6,757)	$ 3,222	$ (3,164)	$ (448)	$ (8,942)	$ 5,753
Net (loss) income per common share:
Basic (in dollars per share)	$ 0.28	$ (0.26)	$ (0.06)	$ 0.02	$ (0.09)	$ (0.29)	$ 0.14	$ (0.14)	$ (0.02)	$ (0.38)	$ 0.29
Diluted (in dollars per share)	$ 0.27	$ (0.26)	$ (0.06)	$ 0.02	$ (0.09)	$ (0.29)	$ 0.14	$ (0.14)	$ (0.02)	$ (0.38)	$ 0.29