Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Apr. 30, 2015
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 96,600	$ 112,900	$ 86,300
Unrecognized Tax Benefits, Period Increase (Decrease)	10,300	1,400
Effect of anticipated settlements of audit issues and expiring statutes of limitations	8,500
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	14,500
Accrued income taxes	$ 67,732	$ 147,000	$ 434,684
Effective tax rate, excluding discrete tax items	37.50%	37.80%
Effective Income Tax Rate Reconciliation, Percent	43.70%	41.00%
Net Discreet Tax Expense (Benefit)	$ (26,600)	$ (12,100)