Summary of Significant Accounting Policies - Schedule of Impact of the Change in Contract Estimates on Operating Results (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2015
Change in Accounting Estimate [Line Items]
Favorable effect of the changes in contract estimates on net (loss) income	$ 7.0	$ (52.0)	$ 12.6	$ 24.3	$ 5.9	$ 18.1	$ (11.1)	$ 5.9	$ 5.1	$ (9.2)	$ 18.0	$ (16.2)
Favorable effect of the changes in contract estimates on basic net (loss) income per share (in USD per share)	$ 0.11					$ 0.26	$ (0.17)	$ 0.09	$ 0.08	$ (0.13)	$ 0.27	$ (0.27)
Favorable effect of the changes in contract estimates on diluted net (loss) income per share (in USD per share)	$ 0.10					$ 0.25	$ (0.17)	$ 0.09	$ 0.08	$ (0.13)	$ 0.27	$ (0.27)
Aerospace and Defense | Contracts Accounted for under Percentage-of-Completion
Change in Accounting Estimate [Line Items]
Favorable effect of the changes in contract estimates on income (loss) before income taxes	$ 11.7									$ 37.2	$ 14.1	$ 41.2
Favorable effect of the changes in contract estimates on net (loss) income	$ 7.0									$ 22.3	$ 8.5	$ 24.7
Favorable effect of the changes in contract estimates on basic net (loss) income per share (in USD per share)	$ 0.11									$ 0.31	$ 0.13	$ 0.40
Favorable effect of the changes in contract estimates on diluted net (loss) income per share (in USD per share)	$ 0.09									$ 0.31	$ 0.11	$ 0.40