Divestitures and Discontinued Operations - Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Loss from discontinued operations, net of income taxes	$ 0	$ 0	$ 0	$ (179,466)
Natural Gas Storage Assets | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Total revenues		0		22,836
Total costs and expenses and other, net, excluding depreciation and amortization		0		(15,360)
Depreciation and amortization		0		(8,161)
Other operating loss		0		(178,781)
Loss from discontinued operations before income taxes		0		(179,466)
Income tax expense		0		0
Loss from discontinued operations, net of income taxes		$ 0		$ (179,466)