INTANGIBLE AND OTHER ASSETS: (Details Textual) (USD $)	12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Amortization of Intangible Assets	$ 1,714,000	$ 1,813,000	$ 1,922,000
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	1,600,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two	1,600,000
Finite-Lived Intangible Assets, Amortization Expense, Year Three	1,500,000
Finite-Lived Intangible Assets, Amortization Expense, Year Four	1,500,000
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 1,500,000