Discontinued Operations (Details) (USD $)	3 Months Ended				12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax					$ 0	$ 8,203,000	$ 9,868,000
Discontinued Operation Income Loss From Discontinued Operation Disclosures Abstract
Operating revenues						37,962,000	114,703,000
Purchased gas cost						21,464,000	62,902,000
Gross profit						16,498,000	51,801,000
Operating expenses						5,858,000	24,174,000
Operating income						10,640,000	27,627,000
Discontinued Operations Miscellaneous Income Expense						548,000	611,000
Income from discontinued operations before income taxes						11,188,000	28,238,000
Income tax expense					0	3,986,000	10,066,000
Income (loss) from discontinued operations	0	0	4,085,000	3,117,000	0	7,202,000	18,172,000
Gain on sale of discontinued operations, net of tax	0	5,294,000	0	0	0	5,294,000	6,349,000
Net income (loss) from discontinued operations					0	12,496,000	24,521,000
Missouri, Illinois and Iowa [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Cash Price Received from Disposal of Discontinued Operation						128,000,000
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax						9,900,000
Georgia [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued Operation, Cash Price Received from Disposal of Discontinued Operation					153,000,000
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax					$ 8,200,000