Revenue - Schedule of Contract Assets and Liabilities (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Contract assets	$ 49.3	$ 51.5
Contract liabilities	23.7	29.1
Net contract assets	25.6	$ 22.4
$ Change
Contract assets	(2.2)
Contract liabilities	(5.4)
Net contract assets	$ 3.2
% Change
Contract assets	(18.60%)
Contract liabilities	(4.30%)
Net contract assets	14.30%