EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Basic EPS:
Net Income	$ 14.1	$ 11.7	$ 155.6	$ 99.5
Less: Income allocated to participating securities	0.1	0.0	0.5	0.4
Net Income Available to Common Shareholders	$ 14.0	$ 11.7	$ 155.1	$ 99.1
Weighted Average Shares Outstanding, Basic (in Shares)	43,200	34,900	43,100	33,300
Basic Earnings Per Share of Common Stock (in dollars per share)	$ 0.32	$ 0.34	$ 3.59	$ 2.97
Diluted EPS:
Net Income	$ 14.1	$ 11.7	$ 155.6	$ 99.5
Less: Income allocated to participating securities	0.1	0.0	0.5	0.4
Net Income Available to Common Shareholders	$ 14.0	$ 11.7	$ 155.1	$ 99.1
Weighted Average Shares Outstanding, Basic (in Shares)	43,200	34,900	43,100	33,300
Dilutive Effect of Stock Options, Restricted Stock and Restricted Stock Units (in shares)	100	100	100	100
Weighted Average Diluted Shares (in shares)	43,300	35,000	43,200	33,400
Diluted Earnings Per Share of Common Stock (in dollars per share)	$ 0.32	$ 0.33	$ 3.59	$ 2.97
Restricted stock and stock units subject to performance and/or market conditions
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding shares excluded from calculation of diluted EPS (in shares)	300	300	300	300