GOODWILL AND INTANGIBLE ASSETS - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Goodwill
Goodwill, Balance at beginning of period	$ 51,705	$ 4,718
Additions (Note 3)	17,791	46,987
Impairment	(4,719)
Goodwill, Balance at end of period	$ 64,777	$ 51,705