Discontinued Operations - Consolidated Statements of Cash Flows for the Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation of fixed assets	$ 45,264	$ 51,907	$ 87,871	$ 102,503	$ 129,014	$ 150,592	$ 154,599	$ 197,585	$ 206,113
Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation of fixed assets							48,257	75,762	83,195
Amortization of stock-based awards							2,436	1,913	2,663
Capital expenditures							(71,026)	(47,783)	(132,829)
Discontinued Operations | Government
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation of fixed assets							3,962	3,625	2,624
Amortization of stock-based awards							2,313	1,810	2,537
Capital expenditures							(2,978)	(6,927)	(3,880)
Discontinued Operations | AMECO
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation of fixed assets							44,295	72,137	80,571
Amortization of stock-based awards							123	103	126
Capital expenditures							$ (68,048)	$ (40,856)	$ (128,949)