EMPLOYEE BENEFIT PLANS - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Retirement Benefits [Abstract]
Settlement expense	$ 398,000	$ 0	$ 1,413,000	$ 0
Employer contribution			0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 774,000	$ 385,000	$ 2,165,000	$ 770,000