COMMON STOCK EQUITY - NARRATIVE (Details) - USD ($) shares in Thousands, $ in Millions	6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Equity [Abstract]
Equity raised through the DRP	$ 9.9	$ 9.7
Number of treasury shares issued from raising of equity through the DRP	242	279
Equity raised through the DRP waiver discount feature	$ 22.7
Shares issued through the DRP waiver discount feature (in shares)	554