Basis of Presentation and Summary of Significant Accounting Policies - Revenue Recognition (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) business_unit	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Revenue Recognition [Abstract]
Number of business units in which sales incentive programs are significant | business_unit	1
Revenues recognized under percentage of completion method	$ 255.5	$ 336.1	$ 361.8
Costs and estimated earnings on uncompleted contracts
Costs incurred on uncompleted contracts	1,261.3	1,191.4
Estimated earnings (loss) to date	(59.9)	25.0
Aggregate costs incurred on uncompleted contracts and estimated earnings to date	1,201.4	1,216.4
Less: Billings to date	(1,202.0)	(1,235.8)
Billings in excess of costs and estimated earnings	(0.6)	(19.4)
Billings in excess of costs and estimated earnings
Costs and estimated earnings in excess of billings	28.8	33.9
Billings in excess of costs and estimated earnings on uncompleted contracts	(29.4)	(53.3)
Net costs and estimated earnings in excess of billings (billings in excess of costs and estimated earnings)	$ (0.6)	$ (19.4)
Minimum
Revenue Recognition [Abstract]
Period for receivables to be collected	1 year