Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2012	Apr. 30, 2011
Income Taxes [Abstract]
Accrued expenses	$ 21,533	$ 46,607
Allowance for credit losses and related reserves	102,819	94,796
Valuation allowance	(33,672)	(47,300)
Current	90,680	94,103
Deferred and stock-based compensation	23,590	69,114
Deferred revenue	26,181	23,166
Net operating loss carryovers	18,202	19,850
ASC 740 asset related to unrecognized tax benefits	31,824	32,481
Capital loss carryover	85,778	150,876
Other	2,901	15,636
Valuation allowance	(43,771)	(93,122)
Noncurrent	144,705	218,001
Deferred tax asset	235,385	312,104
Prepaid expenses	(3,641)	(1,674)
Current	(3,641)	(1,674)
Property and equipment	(19,454)	(11,182)
Basis difference in mortgage-related investment	(63,115)	(49,751)
Intangibles	(33,935)	(53,352)
Noncurrent	(116,504)	(114,285)
Net deferred tax assets	$ 115,240	$ 196,145