Accumulated Other Comprehensive Loss ("AOCL") - Summary of Accumulated Other Comprehensive Income (Loss) (Details) $ in Thousands	12 Months Ended
	Apr. 30, 2016 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 1,514,123
Ending Balance	1,441,746
Cash Flow Hedges [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(18,668)
Other comprehensive loss before reclassifications	0
Amounts reclassified from AOCL	1,934
Ending Balance	(16,734)
Currency Translation Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(41,678)
Other comprehensive loss before reclassifications	(20,635)
Amounts reclassified from AOCL	11,083
Ending Balance	(51,230)
Total [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(60,346)
Other comprehensive loss before reclassifications	(20,635)
Amounts reclassified from AOCL	13,017
Ending Balance	$ (67,964)