BENEFIT PLANS: (Details Textual) (USD $)	1 Months Ended		12 Months Ended
	Aug. 31, 2012	Sep. 30, 2006	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011	Aug. 16, 2012
Pension Benefit Plan Accelerated Funding			$ 11,688,000
Pension Contributions	3,000,000		4,572,000	1,407,000	1,075,000
Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities						8,688,000
Percentage Of Line Of Credit						110.00%
Escrow Deposit Percentage						100.00%
Defined Benefit Plan, Target Plan Asset Allocations			100.00%	100.00%
Expected long-term rate of return on assets on assets			8.00%	8.00%	8.00%
Expected Pension Contributions			784,000
Defined Benefit Plan Expected Future Benefit Payments For First Five Years Following Fiscal Year Description			The amount of future annual benefit payments is expected to be between $2,400,000 and $2,600,000 in fiscal years 2014 through 2018,
Defined Benefit Plan Expected Future Benefit Payments For Second Five Years Following Fiscal Year Description			an aggregate of approximately $11,600,000 is expected to be paid in the fiscal five-year period 2019 through 2023.
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period		400,000
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax, Total			734,000	3,158,000	60,000
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax			$ 1,662,000	$ 0	$ 0
Fixed Income Securities [Member]
Defined Benefit Plan, Target Plan Asset Allocations			21.00%	20.00%
Other Current Assets [Member]
Defined Benefit Plan, Target Plan Asset Allocations			1.00%
Equity Securities [Member]
Defined Benefit Plan, Target Plan Asset Allocations			78.00%