RESTRUCTURING AND OTHER RELATED CHARGES - Rollforward of Restructuring Liability - Furmanite Belgium and Netherlands Exit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits), net	$ 6,727	$ 2,651	$ 5,513
Furmanite Netherlands and Belgium Exit
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits), net		(1,229)	5,513
Employee Severance | Furmanite Netherlands and Belgium Exit
Restructuring Cost and Reserve [Line Items]
Balance, beginning of period	$ 0	4,846
Restructuring and other related charges (credits), net		(173)
Payments		(3,144)
Disposal		(1,601)
Foreign currency adjustments		72
Balance, end of period		0	4,846
MS | Employee Severance | Furmanite Netherlands and Belgium Exit
Restructuring Cost and Reserve [Line Items]
Restructuring and other related charges (credits), net		$ (173)	$ 4,862