Utility Regulatory Assets and Liabilities and Regulatory Matters (Details Textual) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Regulatory Assets [Line Items]
Gas utility unrealized gains or losses on derivative financial instruments contracts	$ 2.0	$ (1.7)	$ (0.4)
Fair Value of Electric Utility Electricity Supply Contracts	$ (3.2)	$ (4.8)	$ 8.2