Intangible and Other Assets, Net (Details) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2012	Apr. 30, 2012
Finite-Lived Intangible Assets, Gross	$ 22,934	$ 23,270
Deferred order entry costs	1,257	1,320
Prepaid expenses	3,306	3,315
Finite-Lived Intangible Assets, Accumulated Amortization	9,810	9,290
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Assets, Gross	1,706	1,964
Finite-Lived Intangible Assets, Accumulated Amortization	1,682	1,905
Customer Contracts and Relationships [Member]
Finite-Lived Intangible Assets, Gross	15,000	15,000
Finite-Lived Intangible Assets, Accumulated Amortization	7,236	6,612
Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Gross	1,665	1,671
Finite-Lived Intangible Assets, Accumulated Amortization	892	773
Deferred Order Entry Costs [Member]
Finite-Lived Intangible Assets, Accumulated Amortization	0	0
Prepaid Expenses [Member]
Finite-Lived Intangible Assets, Accumulated Amortization	$ 0	$ 0