CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - UNAUDITED (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - UNAUDITED [Abstract]
Net Income	$ 36,197	$ 43,057	$ 72,130	$ 79,174
Other Comprehensive Income (Loss):
Foreign currency translation adjustment	50,940	35,039	41,137	(5,958)
Unamortized retirement costs, net of tax (benefit) provision of $(253), $252, $881and $1,778, respectively	(1,106)	269	1,699	3,895
Unrealized gain (loss) on interest rate swaps, net of tax (benefit) provision of $35, $175, $198 and $(55), respectively	57	292	333	(88)
Total Other Comprehensive Income (Loss)	49,891	35,600	43,169	(2,151)
Comprehensive Income	$ 86,088	$ 78,657	$ 115,299	$ 77,023