Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Apr. 30, 2015
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 76,500	$ 128,100	$ 86,300
Unrecognized Tax Benefits, Period Increase (Decrease)	9,800	16,600
Effect of anticipated settlements of audit issues and expiring statutes of limitations	15,000
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	8,700
Accrued income taxes	$ 245,541	$ 284,038	$ 434,684
Effective tax rate, excluding discrete tax items	37.40%	38.10%
Effective Income Tax Rate Reconciliation, Percent	48.40%	38.10%
Net Discreet Tax Expense (Benefit)	$ 20,600	$ 100