SHARE BASED COMPENSATION PLANS - Summary of Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Number of Shares [Roll Forward]
Options outstanding, beginning of period (in shares)	125,560	189,088
Granted (in shares)	0	0	0
Exercised (in shares)	(29,386)	(63,528)
Forfeited or expired (in shares)	(20,417)	0
Options outstanding, end of period (in shares)	75,757	125,560	189,088
Options exercisable end of year (in shares)	75,757	125,560
Weighted Average Exercise Price [Roll Forward]
Options outstanding, beginning of period (in dollars per share)	$ 25.73	$ 25.74
Granted (in dollars per share)	0.00	0.00
Exercised (in dollars per share)	33.38	25.77
Forfeited or expired (in dollars per share)	26.25	0.00
Options outstanding, end of period (in dollars per share)	22.62	25.73	$ 25.74
Options exercisable end of year (in dollars per share)	$ 22.62	$ 25.73
Weighted Average Remaining Contractual Term (Yrs) [Abstract]
Options outstanding , weighted average remaining contractual term (Yrs)	2 years 3 months 10 days	2 years 8 months 5 days	3 years 1 month 28 days
Options exercisable end of year, weighted average remaining contractual term (Yrs)	2 years 3 months 10 days	2 years 8 months 5 days
Aggregate Intrinsic Value [Abstract]
Options outstanding, beginning of period	$ 4,379	$ 3,027
Granted	0	0
Exercised	1,790	1,510	$ 900
Forfeited or expired	1,464	0
Options outstanding, end of period	$ 4,225	4,379	$ 3,027
Options exercisable end of year		$ 4,379