SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND PRACTICES - Schedule of Rollforward Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Goodwill [Roll Forward]
Balance at beginning of period	$ 281,650
Foreign currency adjustments	(980)
Balance at end of period	280,670
IHT
Goodwill [Roll Forward]
Balance at beginning of period	192,608
Foreign currency adjustments	178
Balance at end of period	192,786
MS
Goodwill [Roll Forward]
Balance at beginning of period	55,627
Foreign currency adjustments	(613)
Balance at end of period	55,014
Quest Integrity
Goodwill [Roll Forward]
Balance at beginning of period	33,415
Foreign currency adjustments	(545)
Balance at end of period	$ 32,870