EMPLOYEE BENEFIT PLANS - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Components of the net periodic pension expense (benefit)
Interest cost	$ 1,097	$ 1,097	$ 3,291	$ 3,291
Expected return on plan assets	(1,381)	(1,386)	(4,143)	(4,158)
Recognized net actuarial loss	669	291	2,007	874
Settlement	1,814	1,548	1,814	1,548
Net pension expense	$ 2,199	$ 1,550	$ 2,969	$ 1,555