Divestitures and Discontinued Operations - Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations, net of income taxes	$ 0	$ 1,102
Natural Gas Storage Assets | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues		10,934
Total costs and expenses and other, net, excluding depreciation and amortization		(5,751)
Depreciation and amortization		(4,081)
Income from discontinued operations before income taxes		1,102
Income tax expense		0
Income from discontinued operations, net of income taxes		$ 1,102