Intangible Assets - Narrative (Details) - Customer relationships - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 20.3	$ 17.8	$ 28.6
Major Energy Companies, Provider Companies, And Verde Companies
Finite-Lived Intangible Assets [Line Items]
Amortization expense	16.5	(15.0)	27.2
Cost of revenues
Finite-Lived Intangible Assets [Line Items]
Amortization expense			15.8
Cost of revenues | Major Energy Companies, Provider Companies, And Verde Companies
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ (1.2)	$ 0.3	$ 15.8