Operating Information by Segment and Geographic Area - Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenue	$ 4,118,556	$ 4,133,612
Corporate G&A	14,052	(58,621)
Impairment, restructuring and other exit costs	297,604	27,368
Earnings (loss) from continuing operations before taxes	(228,426)	(28,974)
Continuing Operations
Segment Reporting Information [Line Items]
Corporate G&A	14,100	(58,600)
Impairment, restructuring and other exit costs	297,600	27,400
Interest income (expense), net	(6,300)	(5,700)
Earnings (loss) attributable to NCI from continuing operations	9,500	23,800
Earnings (loss) from continuing operations before taxes	(228,400)	(29,000)
Continuing Operations \| Reportable segments
Segment Reporting Information [Line Items]
Revenue	4,118,600	4,133,600
Segment profit (loss)	51,900	38,900
Continuing Operations \| Energy & Chemicals \| Reportable segments
Segment Reporting Information [Line Items]
Revenue	1,355,500	1,474,700
Segment profit (loss)	(6,400)	12,200
Continuing Operations \| Mining and Industrial segment \| Reportable segments
Segment Reporting Information [Line Items]
Revenue	1,173,900	1,051,300
Segment profit (loss)	38,700	27,500
Continuing Operations \| Infrastructure & Power \| Reportable segments
Segment Reporting Information [Line Items]
Revenue	385,900	344,000
Segment profit (loss)	5,200	(21,800)
Continuing Operations \| Government \| Reportable segments
Segment Reporting Information [Line Items]
Revenue	717,700	756,100
Segment profit (loss)	30,900	38,400
Continuing Operations \| Diversified Services \| Reportable segments
Segment Reporting Information [Line Items]
Revenue	457,100	488,400
Segment profit (loss)	5,100	8,700
Continuing Operations \| Other \| Reportable segments
Segment Reporting Information [Line Items]
Revenue	28,500	19,100
Segment profit (loss)	$ (21,600)	$ (26,100)

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