BUSINESS COMBINATIONS AND CONTINGENT CONSIDERATION - Narrative (Details) $ in Thousands		6 Months Ended
	Mar. 31, 2018 USD ($) business	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)
Business Acquisition [Line Items]
Payments to acquire business		$ 187	$ 19
Contingent consideration liability	$ 889	889		$ 311
Certain Assets of a Tax Preparation and Accounting Business
Business Acquisition [Line Items]
Number of businesses acquired | business	5
Payments to acquire business	$ 187
Contingent consideration liability	580	$ 580
Customer relationships | Certain Assets of a Tax Preparation and Accounting Business
Business Acquisition [Line Items]
Assets acquired	$ 767
Estimated useful life	7 years