INTANGIBLE AND OTHER ASSETS (Details) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2015	Apr. 30, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Cost	$ 21,209	$ 22,032
Finite-Lived Intangible Assets, Accumulated Amortization	10,422	9,354
Customer Contracts and Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Cost	16,986	16,986
Finite-Lived Intangible Assets, Accumulated Amortization	10,404	9,342
Prepaid Expenses [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Cost	2,402	3,054
Finite-Lived Intangible Assets, Accumulated Amortization	0	0
Deferred Order Entry Costs [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Cost	1,003	1,168
Finite-Lived Intangible Assets, Accumulated Amortization	0	0
Other [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Cost	818	824
Finite-Lived Intangible Assets, Accumulated Amortization	$ 18	$ 12