SEGMENT AND GEOGRAPHIC DISCLOSURES - Segment Data for our Three Operating Segments (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020		Mar. 31, 2019
Segment Reporting Information [Line Items]
Goodwill impairment charge		$ 191,788		$ 0
Revenues	[1]	236,839		269,599
Operating income (loss)		(212,932)		(16,528)
Capital expenditures	[2]	6,704		6,610
Depreciation and amortization		11,708		12,271
IHT
Segment Reporting Information [Line Items]
Goodwill impairment charge		191,788
Revenues		107,881		127,056
MS
Segment Reporting Information [Line Items]
Goodwill impairment charge		0
Revenues		104,519		121,526
Quest Integrity
Segment Reporting Information [Line Items]
Goodwill impairment charge		0
Revenues		24,439		21,017
Operating segments | IHT
Segment Reporting Information [Line Items]
Revenues		107,881		127,056
Operating income (loss)		(192,150)	[3]	1,721
Capital expenditures	[2]	1,041		968
Depreciation and amortization		3,983		4,502
Operating segments | MS
Segment Reporting Information [Line Items]
Revenues		104,519		121,526
Operating income (loss)		1,022		5,534
Capital expenditures	[2]	3,617		1,963
Depreciation and amortization		5,431		5,414
Operating segments | Quest Integrity
Segment Reporting Information [Line Items]
Revenues		24,439		21,017
Operating income (loss)		6,106		1,644
Capital expenditures	[2]	971		1,328
Depreciation and amortization		886		921
Corporate and shared support services
Segment Reporting Information [Line Items]
Operating income (loss)		(27,910)		(25,427)
Capital expenditures	[2]	1,075		2,351
Depreciation and amortization		$ 1,408		$ 1,434

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

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

[3] Includes goodwill impairment charge for IHT as discussed in Note 7 for the three months ended March 31, 2020.