Borrowings (Schedule Of Borrowings) (Details) (USD $) In Thousands, unless otherwise specified				9 Months Ended			9 Months Ended		9 Months Ended
	Jan. 31, 2013	Apr. 30, 2012	Jan. 31, 2012	Jan. 31, 2013 Senior Notes, 5.125%, Due October 2014 [Member]	Apr. 30, 2012 Senior Notes, 5.125%, Due October 2014 [Member]	Jan. 31, 2012 Senior Notes, 5.125%, Due October 2014 [Member]	Jan. 31, 2013 Senior Notes, 5.500%, Due November 2022 [Member]	Oct. 25, 2012 Senior Notes, 5.500%, Due November 2022 [Member]	Jan. 31, 2013 Senior Notes, 7.875% Due January 2013 [Member]	Apr. 30, 2012 Senior Notes, 7.875% Due January 2013 [Member]	Jan. 31, 2012 Senior Notes, 7.875% Due January 2013 [Member]	Jan. 31, 2013 Other [Member]	Apr. 30, 2012 Other [Member]	Jan. 31, 2012 Other [Member]
Debt Instrument [Line Items]
Commercial paper outstanding	$ 424,967		$ 230,947
Debt, Long-term and Short-term, Combined Amount, Total	906,725	1,040,549	1,040,237	399,588	399,412	399,364	497,260			599,913	599,871	9,877	41,224	41,002
Less: Current portion	(713)	(631,434)	(630,996)
Long-term debt	$ 906,012	$ 409,115	$ 409,241					$ 500,000
Long-term note, interest rate				5.125%			5.50%		7.875%
Senior notes, maturity date				Oct. 01, 2014			Nov. 01, 2022		Jan. 01, 2013