Long-term Debt - Narrative - Senior Credit Facility (Detail) (USD $) In Millions, unless otherwise specified			9 Months Ended				9 Months Ended		9 Months Ended		9 Months Ended
	Aug. 31, 2014	Nov. 30, 2013	Aug. 31, 2014 Senior Credit Facility [Member]	May 30, 2012 First Amendment [Member] Senior Credit Facility [Member]	Aug. 16, 2012 Second Amendment [Member] Senior Credit Facility [Member]	Aug. 31, 2014 Term Loan [Member]	Aug. 31, 2014 Minimum [Member] Senior Credit Facility [Member]	May 30, 2012 Minimum [Member] First Amendment [Member] Senior Credit Facility [Member]	Aug. 31, 2014 Maximum [Member] Senior Credit Facility [Member]	May 30, 2012 Maximum [Member] First Amendment [Member] Senior Credit Facility [Member]	Aug. 31, 2014 Till November 30, 2015 [Member] Maximum [Member] Senior Credit Facility [Member]	Aug. 31, 2014 Till November 30, 2017 [Member] Maximum [Member] Senior Credit Facility [Member]	Aug. 31, 2014 Thereafter [Member] Maximum [Member] Senior Credit Facility [Member]	May 30, 2014 Aerojet Rocketdyne, Aerojet Rocket of DE, Inc., Arde and Arde-Barinco [Member] Third Amendment [Member] Senior Credit Facility [Member]	May 30, 2014 Aerojet Rocketdyne, Aerojet Rocket of DE, Inc., Arde and Arde-Barinco [Member] Minimum [Member] Third Amendment [Member] Senior Credit Facility [Member]
Debt Instrument [Line Items]
Term loan borrowings under credit facility				$ 50.0
Sale leasebacks								20.0		30.0
Second lien indebtedness					510
Maximum term loan to draw					50
Revolving credit facility aggregate principal amount														200.0
Standby letters of credit														100.0
Swingline loans														5.0
Term loan facility principal amount														100.0
Term loan facility amortize percentage															5.00%
Percentage of equity interests owned or held by the loan parties			65.00%
Percentage of non-voting stock owned or held by the loan parties			100.00%
Outstanding letters of credit			58.1
Standby letters of credit outstanding			100.0
Total senior debt	100.0	45.0				100.0
Interest at LIBOR plus basis points			2.50%
Commitment fee basis points			0.50%
Debt instrument, fronting fee per annum, basis points			0.25%
Revolving Loan Facilities To Finance Leveraged Buyout									$ 150.0
Leverage Ratio											4.50	4.25	4.00
Interest Coverage Ratio							2.40