Income Taxes (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Apr. 30, 2014
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 79,300,000	$ 127,500,000	$ 79,300,000	$ 127,500,000	$ 111,500,000
Balance of unrecognized tax benefits possible decrease	8,000,000		8,000,000
Unrecognized Tax Benefits, Period Increase (Decrease)			32,200,000	18,900,000
Effect of anticipated settlements of audit issues and expiring statutes of limitations	1,900,000		1,900,000
Income Taxes Receivable	40,900,000	57,600,000	40,900,000	57,600,000
Accrued income taxes	1,619,000	23,375,000	1,619,000	23,375,000	406,655,000
Effective tax rate, excluding discrete tax items			38.30%	39.20%
Effective Income Tax Rate Reconciliation, Percent			44.90%	39.70%
Net Discreet Tax Expense (Benefit)	$ 18,700,000	$ 3,200,000	$ 30,900,000	$ 3,700,000