SEGMENT AND GEOGRAPHIC DISCLOSURES - Summary of Segment Data for Operating Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenues	$ 852,272	$ 862,615
Segment depreciation and amortization	(29,839)	(31,157)
Segment professional fees, severance and other	(1,482)	(2,372)
Corporate and shared support cost	(54,163)	(65,255)
Operating income (loss)	10,136	(13,276)
Interest expense, net	(47,808)	(55,181)
Loss on debt extinguishment	0	(1,585)
Other income (expense), net	2,682	(1,102)
Loss before income taxes	(34,990)	(71,144)
Capital expenditures	7,498	10,434
Depreciation and amortization	36,295	37,872
Amount included in operating expenses
Segment Reporting Information [Line Items]
Depreciation and amortization	13,730	14,555
Amount included in SG&A expenses
Segment Reporting Information [Line Items]
Depreciation and amortization	22,565	23,317
IHT
Segment Reporting Information [Line Items]
Revenues	426,722	429,559
MS
Segment Reporting Information [Line Items]
Revenues	425,550	433,056
Operating Segments
Segment Reporting Information [Line Items]
Revenues	852,272	862,615
Adjusted operating expenses	615,304	636,543
Adjusted selling, general and administrative expenses	141,348	140,564
Adjusted EBITDA	95,620	85,508
Operating Segments | IHT
Segment Reporting Information [Line Items]
Revenues	426,722	429,559
Adjusted operating expenses	316,831	331,481
Adjusted selling, general and administrative expenses	60,388	60,023
Adjusted EBITDA	49,503	38,055
Capital expenditures	3,675	5,373
Depreciation and amortization	11,778	12,402
Operating Segments | MS
Segment Reporting Information [Line Items]
Revenues	425,550	433,056
Adjusted operating expenses	298,473	305,062
Adjusted selling, general and administrative expenses	80,960	80,541
Adjusted EBITDA	46,117	47,453
Capital expenditures	3,691	5,052
Depreciation and amortization	18,061	18,755
Corporate and shared support services
Segment Reporting Information [Line Items]
Capital expenditures	132	9
Depreciation and amortization	$ 6,456	$ 6,715