EMPLOYEE BENEFIT PLANS - Reconciliation of the Changes in the Pension Benefit Obligations and Fair Value of Pension Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Retirement Benefits [Abstract]
Accumulated Benefit Obligation	$ 116,146	$ 119,845
Changes in projected benefit obligations
Projected benefit obligation at beginning of year	119,845	106,205
Interest cost	3,598	4,389	$ 4,077
Actuarial (gain) loss	4,310	16,914
Benefits paid	(11,607)	(7,663)
Projected benefit obligation at end of year	116,146	119,845	106,205
Change in plan assets
Fair value of plan assets at beginning of year	91,142	94,897
Actual return on plan assets	6,535	3,865
Employer contribution	33	43
Benefits paid	(11,607)	(7,663)
Fair value of plan assets at end of year	86,103	91,142	$ 94,897
Funded status of the plan at end of year	$ (30,043)	$ (28,703)