ACQUISITIONS - Pro Forma Information (Details) (Alagasco, USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Alagasco
Business Acquisition, Pro Forma Information [Abstract]
Total net revenues	$ 2,187.1	$ 2,051.5	$ 1,581.4
Net Income	$ 133.5	$ 102.0	$ 81.7
Earnings per share:
Basic (in dollars per share)	$ 3.11	$ 2.50	$ 2.52
Diluted (in dollars per share)	$ 3.10	$ 2.49	$ 2.51

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The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

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- Definition

The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

+ Details

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- Definition

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

+ Details

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- Definition

The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

+ References

+ Details

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