Debt (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended		12 Months Ended	3 Months Ended		12 Months Ended
	Feb. 28, 2013	Dec. 05, 2012	May 31, 2008	May 31, 2003	May 31, 2008 Revolving Loan [Member]	Feb. 28, 2013 Federal Funds Rate [Member]	Feb. 28, 2013 Eurodollar Rate [Member]	May 31, 2008 Term Loan [Member]	Feb. 28, 2013 Unsecured Debt [Member]	Feb. 28, 2013 Secured Debt [Member]	Nov. 30, 2012 Notes Payable, Other Payables [Member]	Feb. 28, 2013 Standby Letter Of Credit [Member]	Feb. 28, 2013 Loan Agreement [Member]
Credit Facility Sanctioned During Period		$ 425.0	$ 525.0		$ 325.0
Credit Facility Sanctioned								200.0
Additional Credit Facility Sanctioned					150.0
Line of Credit Facility, Expiration Date	Dec. 05, 2017
Line of Credit Facility, Interest Rate During Period						0.50%
Line Of Credit Facility Base Rate Advances	0.18%
Line Of Credit Facility Eurodollar Rate Advances							1.18%
Line of Credit Facility, Commitment Fee Percentage Range Minimum	0.20%
Line of Credit Facility Fee Percentage Range Maximum	0.40%
Line Of Credit Facility Fee Percentage	0.20%
Standby Letters of Credit												6.6	1.4
Credit Lines Available									20.0	27.1
Short-term Debt, Weighted Average Interest Rate	8.90%
Notes Payable, Noncurrent, Value				$ 175.0
Debt Instrument, Interest Rate, Stated Percentage											5.00%