EMPLOYEE BENEFIT PLANS (Details) - Plan assets and benefit obligation of the defined benefit plans - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Change in benefit obligation:
Actuarial (gain) loss	$ (4,167)
Change in plan assets:
Fair value of plan assets at beginning of fiscal year	150,634
Fair value of plan assets at end of fiscal year	145,319	$ 150,634
Pension Plan [Member]
Change in benefit obligation:
Benefit obligation at beginning of fiscal year	161,328	174,337
Interest cost	5,778	5,084	$ 4,892
Benefits paid	(10,790)	(10,531)
Actuarial (gain) loss	21,481	(7,562)
Benefit obligation at end of fiscal year	177,797	161,328	174,337
Change in plan assets:
Fair value of plan assets at beginning of fiscal year	150,680	150,822
Actual return on plan assets	2,606	7,940
Company contributions	3,114	2,449
Benefits paid	(10,790)	(10,531)
Fair value of plan assets at end of fiscal year	145,610	150,680	150,822
Projected benefit obligation in excess of plan assets	32,187	10,648
Amounts recognized in the statement of financial position consist of:
Accrued liabilities	0	0
Other liabilities (long-term)	(32,187)	(10,648)
Total Liabilities	(32,187)	(10,648)
Net actuarial losses	47,663	19,088
Prior service cost	0	0
Deferred taxes	(17,098)	(6,103)
Total Accumulated other comprehensive loss, net of tax	30,565	12,985
Net amount recognized at September 30,	(1,622)	2,337
Accumulated benefit obligations	177,797	161,328
Information for plans with accumulated benefit obligations in excess of plan assets:
ABO	177,797	161,328
PBO	(32,187)	(10,648)
Fair value of plan assets	145,610	150,680
Supplemental Employee Retirement Plan [Member]
Change in benefit obligation:
Benefit obligation at beginning of fiscal year	15,718	32,627
Interest cost	503	544	715
Benefits paid	(1,942)	(3,001)
Actuarial (gain) loss	1,901	(14,452)
Benefit obligation at end of fiscal year	16,180	15,718	32,627
Change in plan assets:
Fair value of plan assets at beginning of fiscal year	0	0
Actual return on plan assets	0	0
Company contributions	1,942	3,001
Benefits paid	(1,942)	(3,001)
Fair value of plan assets at end of fiscal year	0	0	$ 0
Projected benefit obligation in excess of plan assets	16,180	15,718
Amounts recognized in the statement of financial position consist of:
Accrued liabilities	(1,906)	(1,906)
Other liabilities (long-term)	(14,279)	(13,812)
Total Liabilities	(16,185)	(15,718)
Net actuarial losses	6,609	4,965
Prior service cost	14	28
Deferred taxes	(2,374)	(1,597)
Total Accumulated other comprehensive loss, net of tax	4,249	3,396
Net amount recognized at September 30,	(11,936)	(12,322)
Accumulated benefit obligations	16,180	15,718
Information for plans with accumulated benefit obligations in excess of plan assets:
ABO	16,180	15,718
PBO	(16,180)	(15,718)
Fair value of plan assets	$ 0	$ 0