Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue	$ 1,827,889	$ 2,048,124	$ 1,909,482
Cost of services and products	1,663,948	1,949,880	1,780,256
Other Asset Impairment Charges	70,445	159,353
Gross Margin	163,941	98,244	129,226
Selling, general and administrative expense	195,695	214,891	198,259
Goodwill, Impairment Loss	343,880	14,713	76,449
Income from Operations	(446,079)	(290,713)	(145,482)
Interest income	3,083	7,893	9,962
Interest expense, net of amounts capitalized	(43,900)	(42,711)	(37,742)
Equity earnings of unconsolidated affiliates	2,268	1,331	(3,783)
Other Nonoperating Income	(14,269)	(6,621)	(8,788)
Income before Income Taxes	(498,897)	(330,821)	(185,833)
Income Tax Expense (Benefit)	(2,146)	17,623	26,494
Net Income	$ (496,751)	$ (348,444)	$ (212,327)
Basic Earnings per Share	$ (5.01)	$ (3.52)	$ (2.16)
Weighted Average Number of Shares Outstanding, Basic	99,233	98,876	98,496
Diluted Earnings per Share	$ (5.01)	$ (3.52)	$ (2.16)
Weighted Average Number of Shares Outstanding, Diluted	99,233	98,876	98,496