Technology, Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Property, Plant and Equipment [Line Items]
Technology, property and equipment, gross	$ 683,224	$ 610,704
Accumulated depreciation	(468,454)	(417,694)
Total	214,770	193,010
Net book value of capitalized software costs	151,500	121,900
Depreciation expense for capitalized software costs	49,600	42,100	$ 36,500
Capitalized Software and Computer Hardware [Member]
Property, Plant and Equipment [Line Items]
Technology, property and equipment, gross	539,968	460,199
Buildings and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Technology, property and equipment, gross	84,923	86,225
Furniture, Fixtures and Warehouse Equipment [Member]
Property, Plant and Equipment [Line Items]
Technology, property and equipment, gross	54,607	60,460
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Technology, property and equipment, gross	$ 3,726	$ 3,820