Goodwill and Other Intangibles (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Nov. 30, 2011	Nov. 30, 2010	May 31, 2011
Payments to Acquire Businesses, Net of Cash Acquired		$ 9.2	$ 8.0
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets			5.6
Goodwill, Impairment Loss			3.4
Finite-Lived Intangible Assets, Amortization Expense	0.9	0.6	1.4
Math Solutions Business [Member]
Payments to Acquire Businesses, Net of Cash Acquired			8.0
Business Acquisition, Purchase Price Allocation, Goodwill Amount			1.7
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets			5.6
International Entity [Member]
Business Acquisition, Purchase Price Allocation, Goodwill Amount		$ 0.2