Business Combination - Transaction Costs and Restructuring Charges (Details) - USD ($) $ in Millions		3 Months Ended
	Jul. 12, 2017	Mar. 31, 2018	Dec. 31, 2017
Transaction Costs
Transaction costs		$ 0.0	$ 60.0
Contract cancellation and advising fees			23.0
Debt issuance costs			$ 40.9
Restructuring Charges
Severance expense		$ 0.0
Novitex
Transaction Costs
Transaction costs	$ 10.3
Executives
Restructuring Charges
Severance expense	4.6
Other terminations
Restructuring Charges
Severance expense	$ 0.1