SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Accounts Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Opening balance	$ 1,948	$ 2,404
Charged to expense	0	16
Accounts written off	(13)	(20)
Amounts collected	(140)	0
Uncollected archive invoices	(36)	(452)
Ending balance	$ 1,759	$ 1,948