Debt and Financing Arrangements (Tables)

3 Months Ended

12 Months Ended

Jul. 31, 2011

Apr. 30, 2011

Debt and Financing Arrangements (Tables) [Abstract]

Long-term debt

	July 31, 2011		April 30, 2011
4.78% Senior Notes due June 1, 2014	$	100,000	$	100,000
6.12% Senior Notes due November 1, 2015		24,000		24,000
6.63% Senior Notes due November 1, 2018		394,489		380,039
5.55% Senior Notes due April 1, 2022		400,000		400,000
4.50% Senior Notes due June 1, 2025		400,000		400,000
Total long-term debt	$	1,318,489	$	1,304,039

Long-term debt consists of the following:

	April 30,
	2011		2010
7.94% Series C Senior Notes due September 1, 2010	$	0	$	10,000
4.78% Senior Notes due June 1, 2014		100,000		100,000
6.12% Senior Notes due November 1, 2015		24,000		24,000
6.63% Senior Notes due November 1, 2018		380,039		376,000
5.55% Senior Notes due April 1, 2022		400,000		400,000
4.50% Senior Notes due June 1, 2025		400,000		0
Total long-term debt	$	1,304,039	$	910,000
Current portion of long-term debt		0		10,000
Total long-term debt, less current portion	$	1,304,039	$	900,000