EMPLOYEE BENEFIT PLANS - Summary of Changes in the Fair Value of the Pension Plan's Level 3 Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Change in plan assets
Fair value of plan assets at beginning of year	$ 94,897	$ 92,816
Fair value of plan assets at end of year	91,142	94,897
Level 3
Change in plan assets
Fair value of plan assets at beginning of year	116	97
Unrealized gains (losses) relating to property still held at the reporting date	45	19
Fair value of plan assets at end of year	$ 161	$ 116