STOCK-BASED COMPENSATION - NARRATIVE (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	3,291,481
Performance Shares, Market Condition Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)	36,392	31,836	44,576
Performance Shares, Subject to Performance Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)	63,870	59,341	51,931
Deferred compensation related to unvested performance shares, period	1 year 8 months 12 days
Performance share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)	130,509	145,176	156,587	179,916
Deferred compensation related to unvested restricted and performance shares	$ 2,400
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)	58,156	44,168	51,154	73,071
Deferred compensation related to unvested restricted and performance shares	$ 943
Deferred compensation related to unvested performance shares, period	1 year 10 months 24 days
Vesting September 30, 2021 | Performance Shares, Subject to Performance Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)	33,844
Vesting Annually Over Three Year Period Beginning September 30, 2019 | Performance Shares, Subject to Performance Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)	30,026
Award vesting period	3 years
Vesting September 30, 2020 | Performance Shares, Subject to Performance Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)		29,608
Vesting Annually Over Three Year Period Beginning September 30, 2018 | Performance Shares, Subject to Performance Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)		29,733
Award vesting period		3 years
Vesting September 30, 2019 | Performance Shares, Subject to Performance Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)			25,806
Vesting Annually Over Three Year Period Beginning September 30, 2017 | Performance Shares, Subject to Performance Conditions
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)			26,125
Award vesting period			3 years
Vesting Annually Over Three Year Period Beginning October 15, 2019 | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)	29,222
Award vesting period	3 years
Vesting Annually Over Three Year Period Beginning April 2020 | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)	6,062
Award vesting period			3 years
Vesting Annually Over Three Year Period Beginning October 15, 2018 | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)		27,949
Award vesting period		3 years
Vesting Annually Over Three Year Period Beginning October 2017 | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)			22,591
Vesting Annually Over Three Year Period Beginning May 8, 2018 | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted but not issued (in shares)			6,143