Commitments and Contingencies - Additional Information - Environmental Matters (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended									6 Months Ended	0 Months Ended	6 Months Ended			6 Months Ended
	May 31, 2014 LegalMatter	Nov. 30, 2013	May 31, 2014 Minimum [Member]	May 31, 2014 Maximum [Member]	May 31, 2014 Contracting business [Member]	May 31, 2014 Aerojet Rocketdyne- Sacramento [Member]	May 31, 2014 Aerojet Rocketdyne- Sacramento [Member] Scenario, Previously Reported [Member]	May 31, 2014 Aerojet Rocketdyne- Sacramento [Member] Minimum [Member]	May 31, 2014 Aerojet Rocketdyne- Sacramento [Member] Maximum [Member]	May 31, 2014 Environmental Protection Agency [Member] acre	Mar. 14, 2008 Rio Del Oro property [Member] acre	May 31, 2014 Aerojet Rocketdyne- BPOU [Member]	May 31, 2014 Aerojet Rocketdyne- BPOU [Member] Minimum [Member]	May 31, 2014 Aerojet Rocketdyne- BPOU [Member] Maximum [Member]	May 31, 2014 Toledo [Member]	May 31, 2014 Toledo [Member] Minimum [Member]	May 31, 2014 Toledo [Member] Maximum [Member]	May 31, 2014 Wabash National Corporation [Member]	Mar. 31, 2014 Aerojet Rocketdyne, Inc. [Member] Minimum [Member]	Mar. 31, 2014 Aerojet Rocketdyne, Inc. [Member] Maximum [Member]
Site Contingency [Line Items]
Number of environmental remediation matters	40
Environmental remediation term	15 years
Future estimated environmental costs total			$ 163.7	$ 266.0				$ 124.6	$ 197.4				$ 23.7	$ 36.6		$ 0.2	$ 0.5	$ 0.2
Environmental costs above the cumulative limitation	163.7	171.3				124.6						23.7
Environmental obligation funding percent					96.00%
Guarantee obligations	120.0					75.0	20.0					25.0
Non-contaminated land										2,600	400
Project Agreement term	15 years
Project agreement effective date												May 09, 2002
Environmental remediation project termination period												2017-05
Agreement renewal date	Mar. 28, 2014
Percentage of responsibility in all project costs																			68.00%	70.00%
Reserve accrued	0
Total project cost to complete the project																47	49
Net project costs																23.5	24.5
Environmental costs, increase in Company's share															0.1
Accrued environmental costs															0.2
Expenditures recoverable															0			0
Accrued environmental costs																		$ 0.2