Contract Assets and Contract Liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Jan. 01, 2018
Contract with Customer, Asset and Liability
Increase in contract asset due to acquisition	$ 24.3
Increase in contract liability due to acquisition	27.1
ASC 606
Contract with Customer, Asset and Liability
Contract assets	46.4	$ 22.1
Contract liabilities	48.2	$ 21.1
Increase in contract liability opening balance for revenue recognized	$ 10.8