BUSINESS COMBINATIONS - Schedule of Unaudited Pro forma Combined Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Combinations [Abstract]
Revenue	$ 602,754	$ 572,628	$ 556,569
Operating (loss) income	(12,314)	45,257	31,940
Net loss attributable to common stockholders	$ (21,647)	$ (6,685)	$ (12,947)
Basic net loss per common share attributable to common stockholders (in dollars per share)	$ (0.52)	$ (0.16)	$ (0.32)
Diluted net loss per common share attributable to common stockholders (in dollars per share)	$ (0.52)	$ (0.16)	$ (0.32)
Basic and diluted weighted average shares outstanding (in shares)	41,846	41,233	40,642