Summary of Significant Accounting Policies - Narrative (Details) (USD $)	0 Months Ended		3 Months Ended	12 Months Ended			0 Months Ended	1 Months Ended	3 Months Ended	1 Months Ended
	Sep. 01, 2014	Sep. 01, 2013	Nov. 30, 2014 Employees acre	Nov. 30, 2014 Segment Employees acre	Nov. 30, 2013	Nov. 30, 2012	Jun. 14, 2013	Dec. 31, 2014	Feb. 28, 2013	Jul. 31, 2012
Business Acquisition [Line Items]
Number of operating segments				2
Acres of land owned by the company			12,000	12,000
Aggregate consideration, paid in cash				$ (200,000)	$ 411,200,000	$ 0
Net loss increase, attributable to out of period adjustments						200,000
Percentage of ownership interest in subsidiary			100.00%	100.00%
Useful life of property, plant and equipment, net				15 years
Goodwill impairment	0	0
Percentage of tax benefit to be realized				50.00%
Estimated retirement period of assets expected to be retired in 15 years				30 years
Standard warranty period				1 year
Percentage of Net Sales				75.00%
Net sales, disposal group				0	0	0
Proceeds from sale of intellectual property related to solar power contract				7,500,000	0	0
Gain on sale of intellectual property related to solar power contract			6,800,000	6,800,000	0	0
Foreign currency transaction gains and (losses)				300,000	(200,000)	400,000
Percentage of employees under collective bargaining agreements				14.00%
Number of total employees			5,071	5,071
Rocketdyne Business [Member]
Business Acquisition [Line Items]
Business acquisition date, Rocketdyne Business							Jun. 14, 2013
Number of additional periods for termination extension date				4
Time frame of each termination extension period				3 months
Agreement termination date				Jun. 12, 2015
Notice period required to extend termination date				5 days
Net sales				679,400,000	319,400,000
Subsequent Event [Member] | Rocketdyne Business [Member]
Business Acquisition [Line Items]
Extended purchase agreement term								3 months
Aerojet Rocketdyne, Inc. [Member]
Business Acquisition [Line Items]
Fiscal period duration				364 days	371 days	364 days
Additional net sales									27,800,000
Fair Value Adjustment to Inventory [Member] | Cost of Sales [Member]
Business Acquisition [Line Items]
Fair value adjustments due to Rocketdyne Business acquisition				3,200,000	2,200,000					6,300,000
Property, Plant and Equipment [Member]
Business Acquisition [Line Items]
Fair value adjustments due to Rocketdyne Business acquisition					81,900,000
Minimum [Member]
Business Acquisition [Line Items]
Amortization periods for identifiable intangible assets				3 years
Maximum [Member]
Business Acquisition [Line Items]
Amortization periods for identifiable intangible assets				30 years
Company [Member]
Business Acquisition [Line Items]
Research and development expenses				51,900,000	42,900,000	30,300,000
Customers [Member]
Business Acquisition [Line Items]
Research and development expenses				478,000,000	339,100,000	271,800,000
Energy Business [Member] | Aerospace and Defense [Member]
Business Acquisition [Line Items]
Net sales, disposal group				600,000
Cost to divest business				2,000,000
Net Sales [Member] | US Government, Standard Missile Program [Member]
Business Acquisition [Line Items]
Percentage of Net Sales				12.00%	22.00%	25.00%
Net Sales [Member] | US Government, Theater High Altitude Area Defense Program [Member]
Business Acquisition [Line Items]
Percentage of Net Sales				12.00%	4.00%	5.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Minimum [Member]
Business Acquisition [Line Items]
Percentage of Net Sales				10.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Maximum [Member]
Business Acquisition [Line Items]
Percentage of Net Sales				10.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member] | NASA [Member]
Business Acquisition [Line Items]
Percentage of Net Sales					22.00%
Customer Concentration Risk [Member] | Net Sales [Member] | Minimum [Member]
Business Acquisition [Line Items]
Percentage of Net Sales				10.00%
Customer Concentration Risk [Member] | Net Sales [Member] | Maximum [Member]
Business Acquisition [Line Items]
Percentage of Net Sales				10.00%
Customer Concentration Risk [Member] | Net Sales [Member] | NASA [Member]
Business Acquisition [Line Items]
Percentage of Net Sales				11.00%
UTC [Member]
Business Acquisition [Line Items]
Decrease in initial purchase price				55,000,000
Expected future acquisition of ownership interest percentage			50.00%	50.00%
UTC [Member] | Rocketdyne Business [Member]
Business Acquisition [Line Items]
Acquisition, purchase price										550,000,000
Aggregate consideration, paid in cash							411,000,000
Decrease in initial purchase price							55,000,000
Expected future acquisition of ownership interest percentage							50.00%