SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND PRACTICES - Additional Information (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Dec. 01, 2018 USD ($)	Sep. 30, 2019 USD ($) employee country Location	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) employee country segment Location customer	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Accounting Policies [Abstract]
Number of operating segments | segment				3
Number of locations in which company operates (more than) | Location		200		200
Number of countries in which the company operates | country		20		20
Number of employees | employee		6,900		6,900
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment loss	$ 0
Goodwill		$ 280,670		$ 280,670		$ 281,650
Accumulated impairment loss		75,200		75,200		75,200
Income Tax Disclosure [Abstract]
Provision (benefit) for income taxes		(2,546)	$ (4,313)	(3,210)	$ (13,377)
Pre-tax loss		9,603	$ 27,839	$ 28,393	$ 80,508
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
IHT
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill		192,786		$ 192,786		192,608
Accumulated impairment loss		21,100		21,100		21,100
MS
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill		55,014		55,014		55,627
Accumulated impairment loss		$ 54,100		$ 54,100		$ 54,100