Organization and Basis of Presentation - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Sep. 02, 2014	Sep. 30, 2014	Sep. 30, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax gain on disposal of discontinued operations		$ 726,410	$ 724,743
Alabama Gas Corporation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount of consideration received	$ 1,600,000
Amount of debt assumed	267,000
Proceeds from sale	1,320,000
Pre-tax gain on disposal of discontinued operations	$ 726,500