SEGMENT AND GEOGRAPHIC DISCLOSURES - Segment Data for our Three Operating Segments (Detail) - USD ($) $ in Thousands		3 Months Ended									12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017		Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenues		$ 309,799	$ 290,856	$ 343,889	$ 302,385	$ 316,334	$ 285,067		$ 312,256	$ 286,554	$ 1,246,929	$ 1,200,211	$ 1,196,696
Operating income (loss)		$ (6,941)	$ (19,694)	$ 1,799	$ (14,125)	$ (2,213)	$ (94,116)	[1]	$ (6,693)	$ (12,088)	(38,961)	(115,110)	(3,118)
Capital expenditures	[2]										25,931	36,798	45,843
Depreciation and amortization											64,862	52,143	48,673
IHT
Segment Reporting Information [Line Items]
Revenues											617,378
MS
Segment Reporting Information [Line Items]
Revenues											532,365
Quest Integrity
Segment Reporting Information [Line Items]
Revenues											97,186
Operating Segments | IHT
Segment Reporting Information [Line Items]
Revenues											617,378	588,441	589,478
Operating income (loss)	[3]										37,329	11,128	43,367
Capital expenditures	[2]										7,643	10,505	8,803
Depreciation and amortization											18,810	19,279	19,853
Operating Segments | MS
Segment Reporting Information [Line Items]
Revenues											532,365	529,973	539,627
Operating income (loss)	[3]										6,323	(33,993)	27,283
Capital expenditures	[2]										11,141	17,791	15,077
Depreciation and amortization											36,177	23,412	21,387
Operating Segments | Quest Integrity
Segment Reporting Information [Line Items]
Revenues											97,186	81,797	67,591
Operating income (loss)											20,138	12,337	4,780
Capital expenditures	[2]										3,526	3,316	2,007
Depreciation and amortization											4,285	4,423	5,323
Corporate and shared support services
Segment Reporting Information [Line Items]
Operating income (loss)											(102,751)	(104,582)	(78,548)
Capital expenditures	[2]										3,621	5,186	19,956
Depreciation and amortization											$ 5,590	$ 5,029	$ 2,110

[1] Includes a goodwill impairment loss of $75.2 million in the third quarter of 2017.

[2] Excludes capital leases. Totals may vary from amounts presented in the consolidated statements of cash flows due to the timing of cash payments.

[3] Includes goodwill impairment loss of $21.1 million and $54.1 million for IHT and MS, respectively, for the year ended December 31, 2017.