Revisions in Estimates - Schedule of Projects Summarized (Details) - Downward Estimate Change [Member] $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($) project	Sep. 30, 2017 USD ($) project	Sep. 30, 2018 USD ($) project	Sep. 30, 2017 USD ($) project
Change In Accounting Estimate [Line Items]
Number of projects with downward estimate changes | project	2	1	4	6
Range of reduction in gross profit from each project, net		$ (12.7)
Increase (decrease) on project profitability	$ 19.3	$ 12.7	$ 57.8	$ 56.8
Minimum [Member]
Change In Accounting Estimate [Line Items]
Range of reduction in gross profit from each project, net	(7.3)		(5.2)	(5.1)
Maximum [Member]
Change In Accounting Estimate [Line Items]
Range of reduction in gross profit from each project, net	$ (12.0)		$ (25.6)	$ (14.5)