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, 2019	Sep. 30, 2018	Sep. 30, 2017
Retirement Benefits [Abstract]
Accumulated Benefit Obligation	$ 119,845	$ 106,205
Changes in projected benefit obligations
Projected benefit obligation at beginning of year	106,205	109,976
Interest cost	4,389	4,077	$ 4,053
Actuarial (gain) loss	16,914	(2,143)
Benefits paid	(7,663)	(5,705)
Projected benefit obligation at end of year	119,845	106,205	109,976
Change in plan assets
Fair value of plan assets at beginning of year	94,897	92,816
Actual return on plan assets	3,865	7,754
Employer contribution	43	32
Benefits paid	(7,663)	(5,705)
Fair value of plan assets at end of year	91,142	94,897	$ 92,816
Funded status of the plan at end of year	$ (28,703)	$ (11,308)