EMPLOYEE BENEFIT PLANS - Components of net periodic pension expense (benefit) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Components of the net periodic pension expense (benefit)
Interest cost	$ 1,097	$ 1,014
Expected return on plan assets	(1,386)	(1,386)
Recognized net actuarial loss	292	461
Net pension expense	3	$ 89
Employer Contributions
Employer contribution	$ 0