Reconciliation of Segment Information, Revenue and Other Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Sales Revenue, Services, Other	$ 13,053	$ 7,766
Revenue, Net	646,062	491,973
Income (Loss) from Continuing Operations before Income Taxes, Domestic	(87,291)	(67,091)
Depreciation, Depletion and Amortization	148,753	154,988
Segment Reporting - Capital Expenditures	112,978	77,656
Total Revenue and Other Income	698,709	532,828
Total Reportable Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Domestic	(32,487)	195
Other Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Equity Method Investments	2,778	3,594
Sales Revenue, Services, Other	13,053	7,766
Revenue, Net	17,627	7,766
Income (Loss) from Continuing Operations before Income Taxes, Domestic	(50,230)	(66,862)
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(6,619)	(16,997)
Depreciation, Depletion and Amortization	11,104	8,007
Segment Reporting - Capital Expenditures	4,067	1,890
Excludes Gas Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest Income (Expense), Net and Other Non-operating Activity	(44,433)	(49,865)
Related Party Transaction, Expenses from Transactions with Related Party	4,574	(424)
Corporate Adjustments And Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gain (Loss) Estimates on Extinguishment of Debt	822	0
Intersegment Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Sales Revenue, Services, Other	0	0
Revenue, Net	(4,574)	(424)
Income (Loss) from Continuing Operations before Income Taxes, Domestic	(4,574)	(424)
Depreciation, Depletion and Amortization	0	0
Segment Reporting - Capital Expenditures	0	0
Gas Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Equity Method Investments	194,607	248,034
Sales Revenue, Services, Other	0	0
Revenue, Net	304,279	245,357
Income (Loss) from Continuing Operations before Income Taxes, Domestic	(93,502)	(22,879)
Depreciation, Depletion and Amortization	95,348	105,715
Segment Reporting - Capital Expenditures	100,793	62,862
Coalbed Methane [Member] \| Gas Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Sales Revenue, Services, Other	0	0
Revenue, Net	49,428	61,465
Income (Loss) from Continuing Operations before Income Taxes, Domestic	3,608	12,606
Utica Shale [Member] \| Gas Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Sales Revenue, Services, Other	0	0
Revenue, Net	50,980	44,270
Income (Loss) from Continuing Operations before Income Taxes, Domestic	17,807	3,256
Other Gas [Member] \| Gas Segment [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Sales Revenue, Services, Other	0	0
Revenue, Net	47,361	(5,080)
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ (144,886)	$ (58,223)

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Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

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