Condensed Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012	Oct. 31, 2011
Condensed Statements of Comprehensive Income [Abstract]
Net Income	$ 148,847	$ 127,247	$ 259,710	$ 238,770
Other comprehensive income (loss):
Foreign currency translation adjustments	1,553	(14,892)	(3,588)	(18,213)
Cash flow hedging derivative activity, net of tax	(340)	(6,385)	2,501	(14,098)
Pension and other postretirement benefit plans activity, net of tax	2,135	0	4,234	0
Available-for-sale securities activity, net of tax	825	(1,036)	631	(1,169)
Total other comprehensive income (loss)	4,173	(22,313)	3,778	(33,480)
Comprehensive Income	$ 153,020	$ 104,934	$ 263,488	$ 205,290