BUSINESS SEGMENT AND ENTITY WIDE DISCLOSURES - Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Revenues:
Revenues	$ 332,877	$ 377,833
Selling, general and administrative expenses	42,499	40,085
Segment depreciation and amortization	35,623	30,004
Operating income	12,386	32,349
Gain on sale of assets	1,526	1,214
Operating segments
Revenues:
Revenues	332,877	377,833
Employment Costs	82,589	82,339
Materials and Supplies	75,309	95,275
Maintenance & Repairs	48,083	53,102
Fleet and Transportation	10,956	18,627
Other cost of revenues	26,958	27,266
Cost of revenues (exclusive of depreciation and amortization)	243,895	276,609
Employment Costs	17,541	18,022
Enterprise Shared Services	10,328	8,985
Other selling, general and administrative expenses	8,845	8,677
Selling, general and administrative expenses	36,714	35,684
Segment depreciation and amortization	35,604	29,985
Operating income	16,664	35,555
Operating segments | Technical Services
Revenues:
Revenues	311,844	356,394
Employment Costs	77,336	77,152
Materials and Supplies	74,469	94,490
Maintenance & Repairs	45,461	50,306
Fleet and Transportation	10,151	17,835
Other cost of revenues	25,832	26,009
Cost of revenues (exclusive of depreciation and amortization)	233,249	265,792
Employment Costs	15,052	15,577
Enterprise Shared Services	9,859	8,572
Other selling, general and administrative expenses	7,418	7,327
Selling, general and administrative expenses	32,329	31,476
Segment depreciation and amortization	32,263	27,170
Operating income	14,003	31,956
Operating segments | Support Services
Revenues:
Revenues	21,033	21,439
Employment Costs	5,253	5,187
Materials and Supplies	840	785
Maintenance & Repairs	2,622	2,796
Fleet and Transportation	805	792
Other cost of revenues	1,126	1,257
Cost of revenues (exclusive of depreciation and amortization)	10,646	10,817
Employment Costs	2,489	2,445
Enterprise Shared Services	469	413
Other selling, general and administrative expenses	1,427	1,350
Selling, general and administrative expenses	4,385	4,208
Segment depreciation and amortization	3,341	2,815
Operating income	2,661	3,599
Unallocated
Revenues:
Selling, general and administrative expenses	5,785	4,401
Segment depreciation and amortization	19	19
Unallocated corporate expenses	5,804	4,420
Segment Reporting, Reconciling Item, Excluding Corporate Non segment
Revenues:
Gain on sale of assets	$ (1,526)	$ (1,214)