Receivables (Schedule Of Activity In The Allowance For Doubtful Accounts) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Oct. 31, 2012	Oct. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	$ 44,589	$ 47,943
Provision	1,150	2,358
Charge-offs	(2,978)	(1,889)
Ending balance	42,761	48,412
Emerald Advance Lines Of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	6,200	4,400
Provision	310	1,530
Ending balance	6,510	5,930
All Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	38,389	43,543
Provision	840	828
Charge-offs	(2,978)	(1,889)
Ending balance	$ 36,251	$ 42,482