Debt (Details) (USD $)	3 Months Ended				3 Months Ended				3 Months Ended										3 Months Ended
	Feb. 28, 2014	Aug. 31, 2014	May 31, 2014	Aug. 31, 2013	Aug. 31, 2014 Loan Agreement	Feb. 28, 2014 Loan Agreement	Aug. 31, 2014 Minimum Loan Agreement	Aug. 31, 2014 Maximum Loan Agreement	Aug. 31, 2014 Loan Agreement Federal Funds Rate [Member]	Aug. 31, 2014 Loan Agreement Eurodollar [Member]	Aug. 31, 2014 Loan Agreement Eurodollar [Member] Minimum	Aug. 31, 2014 Loan Agreement Base Rate [Member] Minimum	Aug. 31, 2014 Loan Agreement Base Rate [Member] Maximum	Aug. 31, 2014 Loan Agreement London Interbank Offered Rate (LIBOR) [Member] Minimum	Aug. 31, 2014 Loan Agreement London Interbank Offered Rate (LIBOR) [Member] Maximum	Aug. 31, 2014 Unsecured Debt [Member] Domestic Line of Credit [Member]	May 31, 2014 Unsecured Debt [Member] Domestic Line of Credit [Member]	Aug. 31, 2013 Unsecured Debt [Member] Domestic Line of Credit [Member]	Aug. 31, 2014 Unsecured Debt [Member] Foreign Line of Credit [Member]	Aug. 31, 2014 Unsecured Debt [Member] Foreign Line of Credit [Member] Line of Credit [Member]	May 31, 2014 Unsecured Debt [Member] Foreign Line of Credit [Member] Line of Credit [Member]	Aug. 31, 2013 Unsecured Debt [Member] Foreign Line of Credit [Member] Line of Credit [Member]
Debt (Details) [Line Items]
Effective Income Tax Rate Reconciliation, Percent	37.30%
Line of Credit Facility, Current Borrowing Capacity					$ 425,000,000											$ 25.0			$ 48.1
Line of Credit Facility, Expiration Date					Dec. 05, 2017
Debt Instrument, Basis Spread on Variable Rate									0.50%	1.00%	0.18%	0.18%	0.60%	1.18%	1.60%
Line Of Credit Facility Fee Percentage					0.20%		0.20%	0.40%
Line of Credit Facility, Amount Outstanding					185,000,000	0										0	0	0
Line of Credit Facility, Average Outstanding Amount					65.0
Credit Lines Available																			0
Line of Credit Facility, Expiration Period																365 days			364 days
Debt, Long-term and Short-term, Combined Amount		198,900,000	135,800,000	29,200,000																0	0	0
StandbyLettersofCredit					0											4.9
Line of Credit Facility, Remaining Borrowing Capacity																$ 12.6