RECEIVEABLES FROM BROKER-DEALERS AND CLEARING ORGANIZATIONS AND OTHER RECEIVABLES - Schedule of Other Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
Brokers and Dealers [Abstract]
Trailing fees	$ 1,058	$ 1,086
Accounts receivable for tax and accounting services	558	661
Allowance for doubtful accounts - tax and accounting services	(309)	(286)
Advances to registered representatives	674	393
Investment banking receivable	1,465	357
Advisory fees	455	559
Notes receivable	714	746
Other	980	749
Total other receivables, net	$ 5,595	$ 4,265