Commitments and Contingencies Commitments and Contingencies (Details)	1 Months Ended	3 Months Ended
	Dec. 31, 2015 USD ($)	Mar. 31, 2016 USD ($) $ / MMBTU
Other Commitments [Line Items]
Additional expense due to unutilized firm transportation and shortfalls in delivering or transporting minimum volumes under certain commitments		$ 16,000,000
CONSOL Carried Cost Obligation [Member]
Other Commitments [Line Items]
Equity method investment, ownership percentage		50.00%
Maximum amount to be paid each calendar year for funding of future drilling and completion costs		$ 400,000,000
Funding of joint venture's future drilling and completion costs		$ 1,600,000,000
Natural gas price agreed upon benchmark, average		4.00
Consent Decree [Member]
Other Commitments [Line Items]
Civil penalty		$ 4,950,000
Mitigation projects		4,500,000
Supplemental environmental projects		$ 4,000,000
Pending Litigation [Member] | Unfavorable Regulatory Action [Member]
Other Commitments [Line Items]
Reduced penalty	$ 223,475
Maximum reduction to penalty	80.00%