Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Document Period End Date			Jun. 30, 2020
Revenue	$ 427,216	$ 495,781	$ 963,884	$ 989,667
Cost of services and products	384,679	453,798	874,595	920,097
Gross margin	42,537	41,983	89,289	69,570
Selling, general and administrative expense	47,719	51,618	103,460	100,919
Impairment of Intangible Assets, Finite-lived	0	0	68,763	0
Goodwill, Impairment Loss	0	0	303,005	0
Income (loss) from operations	(5,182)	(9,635)	(385,939)	(31,349)
Interest income	511	1,848	1,788	4,452
Interest expense, net of amounts capitalized	(11,611)	(10,199)	24,073	19,623
Equity in income (losses) of unconsolidated affiliates	674	0	1,871	(164)
Other income (expense), net	(3,660)	7	(10,788)	726
Income (loss) before income taxes	(19,268)	(17,979)	(417,141)	(45,958)
Provision (benefit) for income taxes	5,520	$ 17,203	(24,755)	14,051
Net Income (Loss)	$ (24,788)		$ (392,386)	$ (60,009)
Weighted-average shares outstanding
Basic (in shares)	99,273	98,929	99,164	98,822
Diluted (in shares)	99,273	98,929	99,164	98,822
Earnings (loss) per share
Basic (in dollars per share)	$ (0.25)	$ (0.36)	$ (3.96)	$ (0.61)
Diluted (in dollars per share)	$ (0.25)	$ (0.36)	$ (3.96)	$ (0.61)