EQUITY-BASED INCENTIVE AWARDS - Restricted Stock Unit Activity (Details) - Restricted Stock Units	12 Months Ended
	Sep. 30, 2017 $ / shares shares
Number of Shares
Nonvested restricted stock units at the beginning of the period (in shares) | shares	28,567
Granted (in shares) | shares	13,000
Vested (in shares) | shares	(14,046)
Nonvested restricted stock units at the end of the period (in shares) | shares	27,521
Weighted Average Fair Value
Nonvested restricted stock units at the beginning of the period (in dollars per share) | $ / shares	$ 90.96
Granted (in dollars per share) | $ / shares	91.65
Vested (in dollars per share) | $ / shares	94.70
Nonvested restricted stock units at the end of the period (in dollars per share) | $ / shares	$ 92.25