GOODWILL AND INTANGIBLE ASSETS - Summary of Intangible Assets by Intangible Asset Type (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 38,879	$ 36,179
Less accumulated amortization	(28,597)	(28,030)
Intangible assets, net	10,282	8,149
Covenants Not-to-Compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets	19,192	18,092
Less accumulated amortization	(17,025)	(16,851)
Intangible assets, net	2,167	1,241
Client Lists
Finite-Lived Intangible Assets [Line Items]
Intangible assets	19,687	18,087
Less accumulated amortization	(11,572)	(11,179)
Intangible assets, net	$ 8,115	$ 6,908