INTANGIBLE AND OTHER ASSETS (Details) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2014	Apr. 30, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$ 23,533	$ 23,259
Accumulated Amortization	9,199	8,284
Deferred Order Entry Costs [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	1,216	1,278
Accumulated Amortization	0	0
Prepaid Expenses [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	3,648	3,859
Accumulated Amortization	0	0
Customer Contracts and Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	17,048	17,048
Accumulated Amortization	8,983	7,917
Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	1,621	1,074
Accumulated Amortization	$ 216	$ 367