SEGMENT AND GEOGRAPHIC DISCLOSURES - Segment Data for our Three Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Total Revenues	$ 206,715	$ 218,339	$ 648,484	$ 628,917
Total Operating loss	(1,258)	(1,729)	(4,408)	(34,929)
Total Capital expenditures	1,833	4,258	6,130	14,846
Total Depreciation and amortization	9,396	8,987	28,481	27,450
IHT
Segment Reporting Information [Line Items]
Total Revenues	103,857	110,312	322,426	320,033
MS
Segment Reporting Information [Line Items]
Total Revenues	102,858	108,027	326,058	308,884
Operating segments | IHT
Segment Reporting Information [Line Items]
Total Revenues	103,857	110,312	322,426	320,033
Total Operating loss	6,412	7,390	17,683	13,038
Total Capital expenditures	835	2,557	3,857	10,654
Total Depreciation and amortization	3,148	3,022	9,390	9,372
Operating segments | MS
Segment Reporting Information [Line Items]
Total Revenues	102,858	108,027	326,058	308,884
Total Operating loss	6,482	7,655	22,395	15,152
Total Capital expenditures	988	1,427	2,263	3,861
Total Depreciation and amortization	4,656	4,704	14,113	14,222
Corporate and shared support services
Segment Reporting Information [Line Items]
Total Operating loss	(14,152)	(16,774)	(44,486)	(63,119)
Total Capital expenditures	10	274	10	331
Total Depreciation and amortization	$ 1,592	$ 1,261	$ 4,978	$ 3,856