INTANGIBLE AND OTHER ASSETS: (Details Textual) - USD ($)	12 Months Ended
	Apr. 30, 2015	Apr. 30, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 1,453,000	$ 1,319,000
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	1,416,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two	1,414,000
Finite-Lived Intangible Assets, Amortization Expense, Year Three	1,413,000
Finite-Lived Intangible Assets, Amortization Expense, Year Four	1,051,000
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 164,000
Customer-Related Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	12 years