Commitments and Contingencies (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended	12 Months Ended	24 Months Ended
	May 31, 2017	Jun. 30, 2017	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2017	Jun. 30, 2016
Other Commitments [Line Items]
Other Commitment		$ 4,195,000
Firm transportation liability		41,000				$ 0
July - December 2017		485,000
2018		709,000
2019		502,000
2020		347,000
2021		280,000
2022 and Thereafter		1,872,000
Penalty	$ 98,840
Transportation Agreement Commitments
Other Commitments [Line Items]
Other Commitment		1,600,000
Drilling, Equipment, and Purchase Obligations
Other Commitments [Line Items]
Other Commitment		852,000
July - December 2017		306,000
2018		341,000
2019		146,000
2020		22,000
2021		4,000
2022 and Thereafter		33,000
Transportation and Gathering Obligations
Other Commitments [Line Items]
Other Commitment		2,598,000
July - December 2017		116,000
2018		247,000
2019		276,000
2020		250,000
2021		213,000
2022 and Thereafter		1,496,000
Operating Lease Obligations
Other Commitments [Line Items]
Other Commitment		371,000
July - December 2017		24,000
2018		47,000
2019		35,000
2020		33,000
2021		34,000
2022 and Thereafter		198,000
Capital Lease and Other Obligations
Other Commitments [Line Items]
Other Commitment		374,000
July - December 2017		39,000
2018		74,000
2019		45,000
2020		42,000
2021		29,000
2022 and Thereafter		145,000
Consent Decree
Other Commitments [Line Items]
Civil penalty			$ 4,950	$ 54,700
Mitigation projects		4,500
Supplemental environmental projects		$ 4,000
Minimum
Other Commitments [Line Items]
Penalty	$ 24,710
Maximum | Marcellus Shale | Transportation Agreement Commitments
Other Commitments [Line Items]
Term		15 years
Scenario, Forecast | Transportation Agreement Commitments
Other Commitments [Line Items]
Other Commitment					$ 616,000