Income Taxes (Schedule of Significant Components of Deferred Tax Assets and Liabilities of Continuing Operations) (Details) (USD $) In Thousands	Apr. 30, 2011	Apr. 30, 2010
Income Taxes
Accrued expenses, current	$ 61,891	$ 17,554
Allowance for credit losses and related reserves, current	102,587	164,783
Net operating loss carryovers, current		200
Other, current		237
Valuation allowance, current	(47,300)	(1,745)
Deferred tax assets, current	117,178	181,029
Deferred and stock-based compensation, noncurrent	73,398	71,970
Property and equipment, noncurrent		9,071
Deferred revenue, noncurrent	23,166	25,595
Net operating loss carryovers, noncurrent	21,057	26,292
Accrued expenses, noncurrent	32,481	31,892
Capital loss carryover, noncurrent	150,876	144,507
Deferred tax assets other, noncurrent	15,953	15,991
Valuation allowance, noncurrent	(94,261)	(151,838)
Deferred tax assets, noncurrent	222,670	173,480
Deferred tax assets	339,848	354,509
Prepaid expenses, current	(4,734)	(6,337)
Deferred tax liabilities, current	(4,734)	(6,337)
Property and equipment	(10,731)
Basis difference in mortgage-related investment, noncurrent	(49,751)	(81,118)
Intangibles, noncurrent	(139,963)	(124,918)
Deferred tax liability, noncurrent	(200,445)	(206,036)
Net deferred tax assets	$ 134,669	$ 142,136