SHARE-BASED COMPENSATION - Summary of Transactions Involving Stock Options (Details) - $ / shares shares in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
No. of Options
Shares under option, beginning of period	203	376
Changes during the period:
Granted (in shares)	0	0
Assumed - Furmanite acquisition (in shares)	0	132
Exercised (in shares)	(16)	(136)
Cancelled (in shares)	0	(4)
Expired (in shares)	(20)	(45)
Shares under option, end of period	167	323
Exercisable at end of period (in shares)	167	319
Weighted Average Exercise Price
Shares under option, beginning of period (in usd per share)	$ 30.63	$ 25.71
Changes during the period:
Granted (in usd per share)	0.00	0.00
Assumed - Furmanite acquisition (in usd per share)	0.00	33.20
Exercised (in usd per share)	27.91	17.71
Cancelled (in usd per share)	0.00	44.62
Expired (in usd per share)	28.66	35.51
Shares under option, end of period (in usd per share)	31.12	30.52
Exercisable at end of period (in usd per share)	$ 31.12	$ 30.40