Intangible and Other Assets, Net (Details) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Apr. 30, 2012
Finite-Lived Intangible Assets, Gross	$ 22,897	$ 23,270
Deferred order entry costs	1,258	1,320
Prepaid expenses	2,993	3,315
Finite-Lived Intangible Assets, Accumulated Amortization	9,686	9,290
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Assets, Gross	1,964	1,964
Finite-Lived Intangible Assets, Accumulated Amortization	1,930	1,905
Customer Contracts and Relationships [Member]
Finite-Lived Intangible Assets, Gross	15,000	15,000
Finite-Lived Intangible Assets, Accumulated Amortization	6,924	6,612
Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Gross	1,682	1,671
Finite-Lived Intangible Assets, Accumulated Amortization	$ 832	$ 773