Acquisition, (As Restated for fiscal 2013) - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Nov. 30, 2015	Aug. 31, 2015	May. 31, 2015	Feb. 28, 2015	Nov. 30, 2014	Aug. 31, 2014	May. 31, 2014	Feb. 28, 2014	Jun. 14, 2013
Business Acquisition [Line Items]
Goodwill (Cash payment less total identifiable net assets acquired)	$ 158.1	$ 158.1	$ 158.1	$ 158.1	$ 158.1	$ 158.1	$ 158.1	$ 153.1
Rocketdyne Business [Member]
Business Acquisition [Line Items]
Current assets									$ 110.9
Property, plant and equipment, net									203.8
Other non-current assets									4.2
Total tangible assets acquired									318.9
Intangible assets acquired									128.3
Deferred income taxes									13.3
Total assets acquired									460.5
Liabilities assumed, current									(105.5)
Liabilities assumed, non-current									(7.2)
Total identifiable net assets acquired									347.8
Goodwill (Cash payment less total identifiable net assets acquired)									$ 63.2