Acquisition - Summary of Pro Forma Information Related to Results of Operations (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2014	Aug. 31, 2013
Net sales:
As reported	$ 419.5	$ 367.5	$ 1,152.3	$ 897.8
Net income:
Net (loss) income	(9.5)	197.4	(61.8)	171.6
Basic income per share
As reported (in USD per share)	$ (0.17)	$ 3.25	$ (1.06)	$ 2.83
Diluted income per share
As reported (in USD per share)	$ (0.17)	$ 2.39	$ (1.06)	$ 2.13
Rocketdyne Business [Member]
Net sales:
As reported		367.5		897.8
Pro forma		367.5		1,277.4
Net income:
Net (loss) income		197.4		171.6
Pro forma		$ 13.2		$ 26.7
Basic income per share
As reported (in USD per share)		$ 3.25		$ 2.83
Pro forma (in USD per share)		$ 0.22		$ 0.44
Diluted income per share
As reported (in USD per share)		$ 2.39		$ 2.13
Pro forma (in USD per share)		$ 0.18		$ 0.39