Revenue - Schedule of Contract Assets and Liabilities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Contract assets	$ 44.8	$ 51.5
Contract liabilities	25.5	29.1
Net contract assets	19.3	$ 22.4
$ Change
Contract assets	(6.7)
Contract liabilities	(3.6)
Net contract assets	$ (3.1)
% Change
Contract assets	(12.40%)
Contract liabilities	(13.00%)
Net contract assets	(13.80%)