Condensed Consolidating Financial Information - Condensed Consolidating Statements of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Aug. 31, 2014	Aug. 31, 2013
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	$ 34.1	$ 26.5
Cash flows from investing activities:
Purchase of Rocketdyne Business	0.2	(411.2)
Capital expenditures	(31.9)	(38.7)
Other investing activities	0.2
Purchase of investments	0	(0.5)
Net cash provided by (used in) investing activities	(31.7)	(450.4)
Cash flows from financing activities:
Debt repayments / repurchases	(165.0)	(2.0)
Proceeds from issuance of debt	189.0	460.0
Debt issuance costs	(4.2)	(14.7)
Net transfers from (to) parent	0	0
Other financing activities	(64.9)	0.4
Net Cash (Used in) Provided by Financing Activities	(45.1)	443.7
Net (decrease) increase in cash and cash equivalents	(42.7)	19.8
Cash and Cash Equivalents at Beginning of Period	197.6	162.1
Cash and Cash Equivalents at End of Period	154.9	181.9
Eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(0.2)	9.6
Cash flows from investing activities:
Purchase of Rocketdyne Business		0
Capital expenditures	0	0
Other investing activities	0
Purchase of investments		0
Net cash provided by (used in) investing activities	0	0
Cash flows from financing activities:
Debt repayments / repurchases	0	0
Proceeds from issuance of debt	0	0
Debt issuance costs	0	0
Net transfers from (to) parent	0	0
Other financing activities	0	0
Net Cash (Used in) Provided by Financing Activities	0	0
Net (decrease) increase in cash and cash equivalents	(0.2)	9.6
Cash and Cash Equivalents at Beginning of Period	0	(10.3)
Cash and Cash Equivalents at End of Period	(0.2)	(0.7)
Parent [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(15.9)	(7.3)
Cash flows from investing activities:
Purchase of Rocketdyne Business		0
Capital expenditures	(0.1)	0
Other investing activities	0.2
Purchase of investments		0
Net cash provided by (used in) investing activities	0.1	0
Cash flows from financing activities:
Debt repayments / repurchases	(164.8)	(1.9)
Proceeds from issuance of debt	189.0	460.0
Debt issuance costs	(4.2)	(14.7)
Net transfers from (to) parent	22.9	(426.3)
Other financing activities	(64.9)	0.4
Net Cash (Used in) Provided by Financing Activities	(22.0)	17.5
Net (decrease) increase in cash and cash equivalents	(37.8)	10.2
Cash and Cash Equivalents at Beginning of Period	192.7	172.4
Cash and Cash Equivalents at End of Period	154.9	182.6
Guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	51.2	25.7
Cash flows from investing activities:
Purchase of Rocketdyne Business		(411.2)
Capital expenditures	(31.2)	(38.7)
Other investing activities	0
Purchase of investments		(0.5)
Net cash provided by (used in) investing activities	(31.2)	(450.4)
Cash flows from financing activities:
Debt repayments / repurchases	(0.2)	(0.1)
Proceeds from issuance of debt	0	0
Debt issuance costs	0	0
Net transfers from (to) parent	(24.7)	424.8
Other financing activities	0	0
Net Cash (Used in) Provided by Financing Activities	(24.9)	424.7
Net (decrease) increase in cash and cash equivalents	(4.9)	0
Cash and Cash Equivalents at Beginning of Period	4.9	0
Cash and Cash Equivalents at End of Period	0	0
Non-guarantor Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(1.0)	(1.5)
Cash flows from investing activities:
Purchase of Rocketdyne Business		0
Capital expenditures	(0.6)	0
Other investing activities	0
Purchase of investments		0
Net cash provided by (used in) investing activities	(0.6)	0
Cash flows from financing activities:
Debt repayments / repurchases	0	0
Proceeds from issuance of debt	0	0
Debt issuance costs	0	0
Net transfers from (to) parent	1.8	1.5
Other financing activities	0	0
Net Cash (Used in) Provided by Financing Activities	1.8	1.5
Net (decrease) increase in cash and cash equivalents	0.2	0
Cash and Cash Equivalents at Beginning of Period	0	0
Cash and Cash Equivalents at End of Period	$ 0.2	$ 0