BUSINESS SEGMENT INFORMATION - Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Revenues:
Revenues	$ 375,507	$ 188,757	$ 660,131	$ 371,367
Operating income (loss):
Operating income (loss)	60,415	(1,220)	83,450	(11,741)
Interest expense	(222)	(103)	(400)	(483)
Interest income	128	14	143	32
Other income, net	79	616	583	1,123
Income (loss) before income taxes	60,400	(693)	83,776	(11,069)
Depreciation and amortization	20,094	17,896	39,560	35,669
Capital expenditures			50,578	25,875
Identifiable assets	965,079	790,206	965,079	790,206	$ 864,365
Technical Services
Revenues:
Revenues	356,103	176,119	622,452	348,760
Operating income (loss):
Operating income (loss)	59,827	1,429	81,638	(4,334)
Depreciation and amortization			34,682	31,189
Capital expenditures			43,418	21,295
Identifiable assets	702,162	485,058	702,162	485,058
Support Services
Revenues:
Revenues	19,404	12,638	37,679	22,607
Operating income (loss):
Operating income (loss)	3,334	(2,402)	6,114	(5,298)
Depreciation and amortization			4,752	4,344
Capital expenditures			7,066	4,347
Identifiable assets	76,205	73,815	76,205	73,815
Corporate
Operating income (loss):
Operating income (loss)	(4,544)	(3,358)	(9,054)	(6,680)
Depreciation and amortization			126	136
Capital expenditures			94	233
Identifiable assets	186,712	231,333	186,712	231,333
Gain on disposition of assets, net.
Operating income (loss):
Operating income (loss)	$ 1,798	$ 3,111	$ 4,752	$ 4,571