LOANS RECEIVABLE, NET AND RELATED ALLOWANCE FOR LOAN LOSSES (Schedule of Average Recorded Investment in Impaired Loans) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Impaired [Line Items]
Average investment in impaired loans	$ 5,929	$ 9,140	$ 6,478	$ 9,005
One-to four-family residential [Member]
Financing Receivable, Impaired [Line Items]
Average investment in impaired loans	1,878	3,051	2,360	3,307
Commercial real estate [Member]
Financing Receivable, Impaired [Line Items]
Average investment in impaired loans	3,661	5,274	3,771	4,783
Home equity lines of credit [Member]
Financing Receivable, Impaired [Line Items]
Average investment in impaired loans	29	243	15	171
Commercial business [Member]
Financing Receivable, Impaired [Line Items]
Average investment in impaired loans	$ 361	560	$ 332	732
Other [Member]
Financing Receivable, Impaired [Line Items]
Average investment in impaired loans		$ 12		$ 12