Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Aug. 31, 2010	Aug. 31, 2010	Aug. 31, 2011
Income Taxes [Line Items]
Liability for uncertain tax positions, inclusive of tax, interest, and penalties			$ 5.5
If the accrued liability for uncertain tax positions was de-recognized, the amount that would reduce the effective tax rate			3.0
Tax deductions with uncertain timing			1.6
If the tax benefits with uncertain timing were de-recognized, effect on effective income tax rate			0
Accrued interest related to uncertain tax positions			1.3
Accrued penalties related to uncertain tax positions			0.1
If the accrued interest and penalties related to uncertain tax positions were de-recognized, amount that would reduce effective tax rate			0.8
Effective income tax rate	7.60%	24.50%
Federal and State
Income Taxes [Line Items]
Liability for uncertain tax positions, inclusive of tax, interest, and penalties			4.1
Minimum | State
Income Taxes [Line Items]
Expected payments to finalize settlements			2.5
Expected timing of payments to finalize settlements			3
Maximum | State
Income Taxes [Line Items]
Expected payments to finalize settlements			$ 3.0
Expected timing of payments to finalize settlements			6