Discontinued Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
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	$ 0	$ 8,203
Discontinued Operation Income Loss From Discontinued Operation Disclosures Abstract
Operating revenues			37,962
Purchased gas cost			21,464
Gross profit			16,498
Operating expenses			5,858
Operating income			10,640
Discontinued Operations Miscellaneous Income Expense			548
Income from discontinued operations before income taxes			11,188
Income tax expense	0	0	3,986
Income (loss) from discontinued operations	0	0	7,202
Gain (loss) on sale of discontinued operations, net of tax	0	0	5,294
Net income (loss) from discontinued operations	$ 0	$ 0	12,496
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
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax			$ 8,200