STOCK-BASED COMPENSATION - DEFERRED RETENTION STOCK/NON-EMPLOYEE DIRECTOR STOCK (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Scheduled to Vest Immediately | Director
Shares
Number of shares granted (in shares)	34,994	27,696	26,165
Weighted Average Grant Date Fair Value
Granted (in dollars per share)	$ 35.72	$ 42.88	$ 44.80
Total Fair Value of Vested Shares
Compensation costs not yet recognized	$ 313
Deferred retention stock
Shares
Outstanding at beginning of period (in shares)	228,246	243,561	242,082
Number of shares granted (in shares)	2,999	42,358	167,407
Delivered (in shares)	(22,389)	(57,673)	(158,733)
Forfeited (in shares)			(7,195)
Outstanding at end of period (in shares)	208,856	228,246	243,561
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)	$ 46.32	$ 44.67	$ 32.99
Granted/Vested (in dollars per share)	33.34	40.72	47.95
Delivered (in dollars per share)	45.00	35.25	30.32
Forfeited (in dollars per share)			44.41
Outstanding at end of period (in dollars per share)	$ 46.28	$ 46.32	$ 44.67
Total Fair Value of Vested Shares
Delivered	$ 641	$ 2,423	$ 7,145