FAIR VALUE MEASUREMENTS - Additional Information (Detail)	3 Months Ended	9 Months Ended			1 Months Ended
	Feb. 29, 2012 USD ($)	Feb. 29, 2012 USD ($)	Feb. 29, 2012 EUR (€)	Feb. 29, 2012 GBP (£)	Feb. 29, 2012 Foreign currency forward contract	May 31, 2011 Foreign currency forward contract	Feb. 29, 2012 Fair Value, Measurements, Recurring Cross-currency swap USD ($)	May 31, 2011 Fair Value, Measurements, Recurring Cross-currency swap USD ($)	Feb. 29, 2012 Fair Value, Measurements, Recurring Foreign currency forward contract USD ($)	May 31, 2011 Fair Value, Measurements, Recurring Foreign currency forward contract USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts, fair value of liability							$ 13,626,000	$ 20,519,000
Unsecured senior note, interest rate		6.70%	6.70%	6.70%
Unsecured senior note, maturity date		Nov. 01, 2015	Nov. 01, 2015	Nov. 01, 2015
Effective euro fixed-rate borrowing	5.31%	5.31%	5.31%	5.31%
Notional principal amount of cross-currency swap	150,000,000	150,000,000	125,000,000
Foreign currency contracts, fair value of assets									800,000	6,157,000
Foreign currency forward contract, maturity date					Mar. 30, 2012	Nov. 23, 2011
Gain on exchange of notional amounts at maturity, offset by change in exchange rate	500,000
Notional amount of foreign currency forward contract, USD purchased	90,300,000	90,300,000
Notional amount of foreign currencies forward contract sold			€ 59,900,000	£ 6,100,000