Property And Equipment (Components Of Property And Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Apr. 30, 2012
Property, Plant and Equipment [Line Items]
Property and equipment net	$ 267,880	$ 240,772
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment net	108,265	116,939
Computers And Other Equipment
Property, Plant and Equipment [Line Items]
Property and equipment net	112,203	84,067
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment net	38,771	32,458
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment net	4,660	3,365
Land And Other Non-Depreciable Assets
Property, Plant and Equipment [Line Items]
Property and equipment net	1,887	1,892
Construction In Process
Property, Plant and Equipment [Line Items]
Property and equipment net	$ 2,094	$ 2,051