Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Document Period End Date			Sep. 30, 2020
Revenue	$ 439,743	$ 497,647	$ 1,403,627	$ 1,487,314
Cost of services and products	410,092	448,586	1,284,687	1,368,683
Gross margin	29,651	49,061	118,940	118,631
Selling, general and administrative expense	49,396	54,255	152,856	155,174
Impairment of Intangible Assets, Finite-lived	0	0	68,763	0
Goodwill, Impairment Loss	40,875	0	343,880	0
Income (loss) from operations	(60,620)	(5,194)	(446,559)	(36,543)
Interest income	414	2,089	2,202	6,541
Interest expense, net of amounts capitalized	(9,250)	(11,382)	(33,323)	(31,005)
Equity in income (losses) of unconsolidated affiliates	131	554	2,002	390
Other income (expense), net	(2,836)	(3,660)	(13,624)	(2,934)
Income (loss) before income taxes	(72,161)	(17,593)	(489,302)	(63,551)
Provision (benefit) for income taxes	7,204	$ 7,930	(17,551)	21,981
Net Income (Loss)	$ (79,365)		$ (471,751)	$ (85,532)
Weighted-average shares outstanding
Basic (in shares)	99,297	98,930	99,209	98,858
Diluted (in shares)	99,297	98,930	99,209	98,858
Earnings (loss) per share
Basic (in dollars per share)	$ (0.80)	$ (0.26)	$ (4.76)	$ (0.87)
Diluted (in dollars per share)	$ (0.80)	$ (0.26)	$ (4.76)	$ (0.87)