SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND PRACTICES - Additional Information (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2016 USD ($) segment location classification customer	Mar. 31, 2015 USD ($) shares	Dec. 31, 2015 USD ($)	Dec. 01, 2015 USD ($)	Jul. 07, 2015 USD ($)	Dec. 31, 2014 USD ($)
Accounting Policies [Abstract]
Number of operating segments | segment	3
Number of service classifications | classification	3
Number of locations in which company operates (more than) | location	220
Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 88,309,000	$ 35,444,000	$ 44,825,000			$ 44,426,000
Restricted cash	$ 5,000,000		5,000,000
Goodwill impairment			0
Discounted cash flow, forecast period	4 years
Market capitalization in excess of consolidated net assets				$ 482,000,000
Market capitalization in excess of consolidated net assets, percentage				141.00%
Goodwill	$ 294,918,000		256,654,000
Workers compensation our self-insured retention	1,000,000.0
Automobile liability self-insured retention	500,000
General liability claims we have an effective self-insured retention	3,000,000.0
Medical claims, our self-insured retention	175,000
Environmental liability claims, our self-insured retention	1,000,000
Amount of earned but unbilled revenue included in accounts receivable	$ 63,900,000		47,100,000
Options to purchase shares of common stock excluded from the computation of diluted earnings per share | shares		0
Sales Revenue, Net | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Number of customers accounted for more than specified percentage of consolidated revenues | customer	0
Qualspec Group
Significant Accounting Policies [Line Items]
Restricted cash	$ 5,000,000
Goodwill					$ 148,482,000
Europe and Canada
Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 43,300,000		$ 17,500,000