GOODWILL AND IMPAIRMENT CHARGES (Details) - USD ($)		3 Months Ended		12 Months Ended
	Dec. 01, 2020	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, Gross, beginning balance				$ 358,380,000	$ 357,247,000
Accumulated Impairment, beginning balance				(267,029,000)	(75,241,000)
Goodwill, Net, beginning balance				91,351,000	282,006,000
FX Adjustments				(1,476,000)	637,000
Impairment charge	$ 0			(64,632,000)	(191,788,000)	$ 0
Additions				0	496,000
Goodwill, Gross, ending balance		$ 356,904,000		356,904,000	358,380,000	357,247,000
Accumulated Impairment, ending balance		(331,661,000)		(331,661,000)	(267,029,000)	(75,241,000)
Goodwill, Net, ending balance		25,243,000		25,243,000	91,351,000	282,006,000
IHT
Goodwill [Roll Forward]
Goodwill, Gross, beginning balance				212,928,000	214,356,000
Accumulated Impairment, beginning balance				(212,928,000)	(21,140,000)
Goodwill, Net, beginning balance				0	193,216,000
FX Adjustments				0	(1,428,000)
Impairment charge					(191,788,000)
Goodwill, Gross, ending balance		212,928,000		212,928,000	212,928,000	214,356,000
Accumulated Impairment, ending balance		(212,928,000)		(212,928,000)	(212,928,000)	(21,140,000)
Goodwill, Net, ending balance		0		0	0	193,216,000
MS
Goodwill [Roll Forward]
Goodwill, Gross, beginning balance				110,721,000	109,510,000
Accumulated Impairment, beginning balance				(54,101,000)	(54,101,000)
Goodwill, Net, beginning balance				56,620,000	55,409,000
FX Adjustments				(783,000)	1,211,000
Impairment charge			$ (55,800,000)	(55,837,000)
Goodwill, Gross, ending balance		109,938,000		109,938,000	110,721,000	109,510,000
Accumulated Impairment, ending balance		(109,938,000)		(109,938,000)	(54,101,000)	(54,101,000)
Goodwill, Net, ending balance		0		0	56,620,000	55,409,000
Quest Integrity
Goodwill [Roll Forward]
Goodwill, Gross, beginning balance				34,731,000	33,381,000
Accumulated Impairment, beginning balance				0	0
Goodwill, Net, beginning balance				34,731,000	33,381,000
FX Adjustments				(693,000)	854,000
Impairment charge		(8,800,000)		(8,795,000)
Additions				0	496,000
Goodwill, Gross, ending balance		34,038,000		34,038,000	34,731,000	33,381,000
Accumulated Impairment, ending balance		(8,795,000)		(8,795,000)	0	0
Goodwill, Net, ending balance		$ 25,243,000		$ 25,243,000	$ 34,731,000	$ 33,381,000