BUSINESS SEGMENT INFORMATION - Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Revenues:
Revenues	$ 284,624	$ 182,610
Operating income (loss):
Operating income (loss)	23,035	(10,521)
Interest expense	(178)	(380)
Interest income	15	18
Other income, net	504	507
Income (loss) before income taxes	23,376	(10,376)
Depreciation and amortization	19,466	17,773
Capital expenditures	19,084	11,750
Identifiable assets	891,168	800,073	$ 864,365
Technical Services
Revenues:
Revenues	266,349	172,641
Operating income (loss):
Operating income (loss)	21,811	(5,762)
Depreciation and amortization	16,974	15,728
Capital expenditures	16,624	9,648
Identifiable assets	616,961	507,815
Support Services
Revenues:
Revenues	18,275	9,969
Operating income (loss):
Operating income (loss)	2,780	(2,896)
Depreciation and amortization	2,427	1,977
Capital expenditures	2,410	1,937
Identifiable assets	74,021	70,304
Corporate
Operating income (loss):
Operating income (loss)	(4,510)	(3,323)
Depreciation and amortization	65	68
Capital expenditures	50	165
Identifiable assets	200,186	221,954
Gain on disposition of assets, net.
Operating income (loss):
Operating income (loss)	$ 2,954	$ 1,460