Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Apr. 30, 2016
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 106,000	$ 76,500	$ 111,500
Unrecognized Tax Benefits, Period Increase (Decrease)	(5,500)	(9,800)
Effect of anticipated settlements of audit issues and expiring statutes of limitations	7,500
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	13,900
Accrued income taxes and reserves for uncertain tax positions	$ 216,390	$ 245,541	$ 373,754
Effective Income Tax Rate Reconciliation, Percent	40.50%	48.40%
Net Discreet Tax Expense (Benefit)	$ 6,800	$ (20,600)
Effective tax rate, impact of discrete tax items	3.30%	11.00%