BENEFIT PLANS: (Details Textual) - USD ($)	1 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2013	Aug. 30, 2013	Aug. 31, 2012	Jan. 31, 2015	Apr. 30, 2015	Apr. 30, 2014	Dec. 31, 2006
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation, Total					$ 122,000	$ 47,000
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax						$ 2,389,000
Defined Benefit Plan, Target Plan Asset Allocations					100.00%	100.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets					8.00%	8.00%
Pension Contributions					$ 475,000	$ 3,718,000
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 $2,598,000 and $2,791,000 in fiscal years 2016 through 2020, and an aggregate of approximately $12,000,000 is expected to be paid in the fiscal five-year period 2021 through 2025.
Defined Benefit Plan Expected Future Benefit Payments For Second Five Years Following Fiscal Year Description					an aggregate of approximately $12,000,000 is expected to be paid in the fiscal five-year period 2021 through 2025.
Pension Benefit Plan Accelerated Funding					$ 11,688,000
Benefits paid					(4,634,000)	(2,398,000)
Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease)				$ 863,000	1,067,000
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months					1,534,000
Defined Benefit Plan, Expected Future Benefit Payments, Year Two					0
Defined Benefit Plan, Expected Future Benefit Payments, Year Three					$ 0
Stock Issued During Period, Shares, Share-based Compensation, Gross					36,000
Common Stock, Capital Shares Reserved for Future Issuance					364,000
Defined Benefit Plan, Expected Future Benefit Payments, Year Five					$ 2,791,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax				543,000
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent					(1,658,000)	2,389,000
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Including Portion Attributable to Noncontrolling Interest [Member]
Defined Benefit Plan Disclosure [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax				$ 543,000
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent					1,658,000
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefits paid					2,317,000
Defined Benefit Plan, Expected Future Benefit Payments, Year Five					2,598,000
Equity Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period							400,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total					81,000
PBGC [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Contributions	$ 3,243,000	$ 3,243,000	$ 3,000,000			$ 3,243,000
Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities		5,019,000			8,688,000
First Lien Mortgages On Real Property Appraised Value		$ 10,039,000
Defined Pension Plan Real Property Of Mortgage					8,192,000
PBGC [Member] | Subsequent Event [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Contributions Towards Accelerated Funding Liability					$ 426,000
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations					29.00%	27.00%
Fixed Income Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations					20.00%
Fixed Income Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations					50.00%
Other Current Assets [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations					0.00%
Other Current Assets [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations					30.00%
Equity Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations					50.00%
Equity Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations					80.00%