Discontinued Operations - Consolidated Statements of Cash Flows for the Discontinued Operations (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation of fixed assets	$ 129,014	$ 150,592
Capital expenditures	34,827	19,320
Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation of fixed assets	47,512	58,155
Amortization of stock-based awards	4,815	4,381
Capital expenditures	(61,264)	(41,152)
Discontinued Operations | Government
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation of fixed assets	2,952	2,489
Amortization of stock-based awards	4,432	4,064
Capital expenditures	(2,216)	(5,614)
Discontinued Operations | AMECO
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation of fixed assets	44,560	55,666
Amortization of stock-based awards	383	317
Capital expenditures	$ (59,048)	$ (35,538)