SEGMENT AND GEOGRAPHIC DISCLOSURES - Segment Data for our Three Operating Segments (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues		$ 207,303	$ 219,093	$ 189,304	$ 236,839	$ 287,807	$ 290,079	$ 315,829	$ 269,599	$ 852,539	[1]	$ 1,163,314	[1]	$ 1,246,929	[1]
Operating income (loss)		$ (2,361)	$ 2,297	$ (4,366)	$ (212,932)	$ 3,218	$ (1,840)	$ 13,004	$ (16,528)	(217,362)		(2,146)		(38,961)
Capital expenditures	[2]									17,667		31,734		25,931
Depreciation and amortization										45,908		49,059		64,862
IHT
Segment Reporting Information [Line Items]
Revenues										374,740		512,950
MS
Segment Reporting Information [Line Items]
Revenues										392,484		535,372
Quest Integrity
Segment Reporting Information [Line Items]
Revenues										85,315		114,992
Operating Segments | IHT
Segment Reporting Information [Line Items]
Revenues										374,740		512,950		617,378
Operating income (loss)	[3]									(174,638)		24,084		37,329
Capital expenditures	[2]									3,218		7,983		7,643
Depreciation and amortization										14,891		17,616		18,810
Operating Segments | MS
Segment Reporting Information [Line Items]
Revenues										392,484		535,372		532,365
Operating income (loss)										25,879		55,385		6,323
Capital expenditures	[2]									8,767		10,755		11,141
Depreciation and amortization										21,854		21,835		36,177
Operating Segments | Quest Integrity
Segment Reporting Information [Line Items]
Revenues										85,315		114,992		97,186
Operating income (loss)										16,474		28,757		20,138
Capital expenditures	[2]									3,743		4,550		3,526
Depreciation and amortization										3,587		3,557		4,285
Corporate and shared support services
Segment Reporting Information [Line Items]
Operating income (loss)										(85,077)		(110,372)		(102,751)
Capital expenditures	[2]									1,939		8,446		3,621
Depreciation and amortization										$ 5,576		$ 6,051		$ 5,590

[1] Revenues attributable to individual countries/geographic areas are based on the country of domicile of the legal entity that performs the work.

[2] Excludes finance 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 $191.8 million for IHT for the year ended December 31, 2020.