REVENUE - Summary of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 852,272	$ 862,615
Non-Destructive Evaluation and Testing Services
Disaggregation of Revenue [Line Items]
Revenues	336,582	343,713
Repair and Maintenance Services
Disaggregation of Revenue [Line Items]
Revenues	417,853	429,755
Heat Treating
Disaggregation of Revenue [Line Items]
Revenues	68,825	60,101
Other
Disaggregation of Revenue [Line Items]
Revenues	29,012	29,046
IHT
Disaggregation of Revenue [Line Items]
Revenues	426,722	429,559
IHT | Non-Destructive Evaluation and Testing Services
Disaggregation of Revenue [Line Items]
Revenues	336,582	343,713
IHT | Repair and Maintenance Services
Disaggregation of Revenue [Line Items]
Revenues	154	275
IHT | Heat Treating
Disaggregation of Revenue [Line Items]
Revenues	67,893	59,399
IHT | Other
Disaggregation of Revenue [Line Items]
Revenues	22,093	26,172
MS
Disaggregation of Revenue [Line Items]
Revenues	425,550	433,056
MS | Non-Destructive Evaluation and Testing Services
Disaggregation of Revenue [Line Items]
Revenues	0	0
MS | Repair and Maintenance Services
Disaggregation of Revenue [Line Items]
Revenues	417,699	429,480
MS | Heat Treating
Disaggregation of Revenue [Line Items]
Revenues	932	702
MS | Other
Disaggregation of Revenue [Line Items]
Revenues	6,919	2,874
United States
Disaggregation of Revenue [Line Items]
Revenues	637,662	623,763
United States | IHT
Disaggregation of Revenue [Line Items]
Revenues	374,657	364,550
United States | MS
Disaggregation of Revenue [Line Items]
Revenues	263,005	259,213
Canada
Disaggregation of Revenue [Line Items]
Revenues	66,940	84,870
Canada | IHT
Disaggregation of Revenue [Line Items]
Revenues	39,699	49,965
Canada | MS
Disaggregation of Revenue [Line Items]
Revenues	27,241	34,905
Other Countries
Disaggregation of Revenue [Line Items]
Revenues	147,670	153,982
Other Countries | IHT
Disaggregation of Revenue [Line Items]
Revenues	12,366	15,044
Other Countries | MS
Disaggregation of Revenue [Line Items]
Revenues	$ 135,304	$ 138,938