RETIREMENT PLANS (Details) - USD ($)	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Change in Plan Assets:
Fair value of plan assets at beginning of year	$ 6,488,000
Fair value of plan assets at end of year	8,195,000	$ 6,488,000
Amounts recognized in the Consolidated Balance Sheets:
Noncurrent liabilities	$ (6,707,000)	(5,409,000)
Pension Plan
Retirement plans
Period of employee's highest average earnings on which benefits are based	5 years
Change in Projected Benefit Obligation:
Benefit obligation at beginning of year	$ 8,683,000	8,299,000
Service cost	261,000	256,000
Interest cost	364,000	356,000
Actuarial loss	953,000	110,000
Benefits paid	(206,000)	(326,000)
Administrative expenses paid	0	(12,000)
Benefit obligation at end of year	10,055,000	8,683,000
Change in Plan Assets:
Fair value of plan assets at beginning of year	6,488,000	7,022,000
Actual return (loss) on plan assets	813,000	(446,000)
Employer contributions	1,100,000	250,000
Benefits paid	(206,000)	(326,000)
Administrative expenses paid	0	(12,000)
Fair value of plan assets at end of year	8,195,000	6,488,000
Funded status	(1,860,000)	(2,195,000)
Amounts recognized in the Consolidated Balance Sheets:
Noncurrent liabilities	(1,860,000)	(2,195,000)
Net amount	(1,860,000)	(2,195,000)
Amounts recognized in accumulated other comprehensive loss (income) before income taxes:
Net actuarial loss (gain)	3,521,000	3,038,000
Prior service cost (credit)	70,000	77,000
Accumulated other comprehensive loss (income)	3,591,000	$ 3,115,000
Other disclosures
Expected contributions	$ 500,000
Assumptions used to determine fiscal year-end benefit obligations:
Discount rate	3.50%	4.25%
Rate of compensation increase	4.00%	4.00%
Assumptions used to determine net benefit costs (years ended):
Discount rate	4.25%	4.25%
Expected return on plan assets	7.00%	7.00%
Rate of compensation increase	4.00%	4.00%
Net periodic benefit cost for the year:
Service cost	$ 261,000	$ 256,000
Interest cost	364,000	356,000
Expected return on plan assets	(484,000)	(500,000)
Amortization of prior service cost (credit)	5,000	5,000
Amortization of net actuarial loss (gain)	141,000	86,000
Net periodic benefit cost	287,000	203,000
Amounts that are estimated to be amortized from accumulated other comprehensive loss into net periodic benefit cost in the next fiscal year
Prior service cost (credit)	5,000
Net actuarial loss (gain)	163,000
Total amount	168,000
Accumulated benefit obligation	8,566,000	7,420,000
Expected Benefit Payments:
Fiscal year ending September 30, 2017	279,000
Fiscal year ending September 30, 2018	298,000
Fiscal year ending September 30, 2019	284,000
Fiscal year ending September 30, 2020	389,000
Fiscal year ending September 30, 2021	413,000
Fiscal years ending September 30, 2022 through 2026	2,511,000
SERP
Change in Projected Benefit Obligation:
Benefit obligation at beginning of year	1,900,000	1,767,000
Service cost	68,000	62,000
Interest cost	86,000	77,000
Actuarial loss	318,000	0
Benefits paid	(6,000)	(6,000)
Benefit obligation at end of year	2,366,000	1,900,000
Change in Plan Assets:
Employer contributions	6,000	6,000
Benefits paid	(6,000)	(6,000)
Funded status	(2,366,000)	(1,900,000)
Amounts recognized in the Consolidated Balance Sheets:
Current liabilities	(5,000)	(5,000)
Noncurrent liabilities	(2,361,000)	(1,895,000)
Net amount	(2,366,000)	(1,900,000)
Amounts recognized in accumulated other comprehensive loss (income) before income taxes:
Net actuarial loss (gain)	797,000	506,000
Prior service cost (credit)	(70,000)	(76,000)
Accumulated other comprehensive loss (income)	$ 727,000	$ 430,000
Assumptions used to determine fiscal year-end benefit obligations:
Discount rate	3.50%	4.25%
Rate of compensation increase	4.00%	4.00%
Assumptions used to determine net benefit costs (years ended):
Discount rate	4.25%	4.25%
Rate of compensation increase	4.00%	4.00%
Net periodic benefit cost for the year:
Service cost	$ 68,000	$ 62,000
Interest cost	86,000	77,000
Amortization of prior service cost (credit)	(5,000)	(5,000)
Amortization of net actuarial loss (gain)	27,000	24,000
Net periodic benefit cost	176,000	158,000
Amounts that are estimated to be amortized from accumulated other comprehensive loss into net periodic benefit cost in the next fiscal year
Prior service cost (credit)	(5,000)
Net actuarial loss (gain)	36,000
Total amount	31,000
Accumulated benefit obligation	1,822,000	1,458,000
Expected Benefit Payments:
Fiscal year ending September 30, 2017	5,000
Fiscal year ending September 30, 2018	4,000
Fiscal year ending September 30, 2019	3,000
Fiscal year ending September 30, 2020	72,000
Fiscal year ending September 30, 2021	73,000
Fiscal years ending September 30, 2022 through 2026	$ 642,000
Postretirement Medical
Retirement plans
Minimum period of service to be attained for being covered under the plan	20 years
Minimum period of service to be attained at the position of Vice President or higher for being covered under the plan	10 years
Change in Projected Benefit Obligation:
Benefit obligation at beginning of year	$ 1,319,000	1,227,000
Service cost	0	0
Interest cost	56,000	52,000
Actuarial loss	1,111,000	40,000
Benefit obligation at end of year	2,486,000	1,319,000
Change in Plan Assets:
Funded status	(2,486,000)	(1,319,000)
Amounts recognized in the Consolidated Balance Sheets:
Noncurrent liabilities	(2,486,000)	(1,319,000)
Net amount	(2,486,000)	(1,319,000)
Amounts recognized in accumulated other comprehensive loss (income) before income taxes:
Net actuarial loss (gain)	1,001,000	(110,000)
Prior service cost (credit)	0	0
Accumulated other comprehensive loss (income)	$ 1,001,000	$ (110,000)
Assumptions used to determine fiscal year-end benefit obligations:
Discount rate	3.50%	4.25%
Assumptions used to determine net benefit costs (years ended):
Discount rate	4.25%	4.25%
Net periodic benefit cost for the year:
Service cost	$ 0	$ 0
Interest cost	56,000	52,000
Amortization of prior service cost (credit)	0	0
Amortization of net actuarial loss (gain)	0	(5,000)
Net periodic benefit cost	56,000	$ 47,000
Amounts that are estimated to be amortized from accumulated other comprehensive loss into net periodic benefit cost in the next fiscal year
Net actuarial loss (gain)	188,000
Total amount	188,000
Expected Benefit Payments:
Fiscal year ending September 30, 2018	42,000
Fiscal year ending September 30, 2019	44,000
Fiscal year ending September 30, 2020	39,000
Fiscal year ending September 30, 2021	72,000
Fiscal years ending September 30, 2022 through 2026	$ 413,000
Assumed health care cost trend rates related to the measurement of entity's postretirement medical obligations
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year	7.75%	8.00%
Ultimate cost trend rate	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2028	2028
Health care cost trend rates assumed for current fiscal year	8.00%
Effects of one-percentage-point change in the assumed health care cost trend rates
Effect on total service and interest cost components, increase	$ 11,000
Effect on accumulated postretirement benefit obligations, increase	527,000
Effect on total service and interest cost components, decrease	(9,000)
Effect on accumulated postretirement benefit obligations, decrease	$ (416,000)