SEGMENT AND GEOGRAPHIC DISCLOSURES - Segment Data for our Three Operating Segments (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues		$ 862,615	$ 840,208
Operating income (loss)		(13,276)	(39,802)
Capital expenditures		10,434	19,036
Depreciation and amortization	[1]	37,872	37,595
Lease cost - continuing operations
Segment Reporting Information [Line Items]
Depreciation and amortization		37,872	36,453
IHT
Segment Reporting Information [Line Items]
Revenues		429,559	422,562
MS
Segment Reporting Information [Line Items]
Revenues		433,056	417,646
Operating Segments | IHT
Segment Reporting Information [Line Items]
Revenues		429,559	422,562
Operating income (loss)		24,220	17,093
Capital expenditures		5,373	13,939
Operating Segments | IHT | Lease cost - continuing operations
Segment Reporting Information [Line Items]
Depreciation and amortization		12,402	12,391
Operating Segments | MS
Segment Reporting Information [Line Items]
Revenues		433,056	417,646
Operating income (loss)		27,759	20,930
Capital expenditures		5,052	5,013
Operating Segments | MS | Lease cost - continuing operations
Segment Reporting Information [Line Items]
Depreciation and amortization		18,755	19,021
Corporate and shared support services
Segment Reporting Information [Line Items]
Operating income (loss)		(65,255)	(77,825)
Capital expenditures		9	84
Corporate and shared support services | Lease cost - continuing operations
Segment Reporting Information [Line Items]
Depreciation and amortization		$ 6,715	$ 5,041

[1] Consolidated statement of cash flows for the year ended December 31, 2022 includes cash flows from discontinued operations. See Note 2.