RECEIVEABLES FROM BROKER-DEALERS AND CLEARING ORGANIZATIONS AND OTHER RECEIVABLES - Schedule of Other Receivables (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Sep. 30, 2018
Brokers and Dealers [Abstract]
Trailing fees	$ 959	$ 1,086
Accounts receivable for tax and accounting services	1,172	661
Allowance for doubtful accounts - tax and accounting services	(304)	(286)
Advances to registered representatives	757	393
Investment banking receivable	516	357
Advisory fees	464	559
Notes receivable	688	746
Other	888	749
Total other receivables, net	$ 5,140	$ 4,265