Commitments (Details) Bcf in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($) MMBbls Bcf	Dec. 31, 2019 USD ($) MMBbls Bcf	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Commitments and Contingencies
Contractual obligation, due in 2020	$ 102,550,000	$ 102,550,000
Contractual obligation, due in 2021	94,494,000	94,494,000
Contractual obligation, due in 2022	73,826,000	73,826,000
Contractual obligation, due in 2023	41,661,000	41,661,000
Contractual obligation, due in 2024	12,349,000	12,349,000
Contractual obligation, due thereafter	24,697,000	24,697,000
Contractual obligation	349,577,000	$ 349,577,000
Loss on drilling and completion contract terminations	$ 18,200,000
Crude oil pipeline commitment [Member]
Commitments and Contingencies
Oil and gas delivery commitments, remaining minimum contractual volumes | MMBbls	24	24
Natural gas pipeline commitment [Member]
Commitments and Contingencies
Oil and gas delivery commitments, remaining minimum contractual volumes | Bcf	424	424
Crude Oil Pipeline Commitment Excluded from Remaining Deficiency Payment Amount [Member]
Commitments and Contingencies
Oil and gas delivery commitments, remaining minimum contractual volumes | MMBbls	16.5	16.5
Drilling Rig Leasing Contracts [Member]
Commitments and Contingencies
Contractual obligation	$ 34,100,000	$ 34,100,000
Early Termination Penalty for Rig Contract Cancellation	26,300,000	26,300,000
PipelineCommitments [Member]
Commitments and Contingencies
Contractual obligation	218,500,000	218,500,000
Office Space Leases [Member]
Commitments and Contingencies
Contractual obligation	28,300,000	28,300,000
Operating leases, rent expense, net of sublease income		5,500,000	$ 4,500,000	$ 4,800,000
Electricity Purchase Agreement [Member]
Commitments and Contingencies
Contractual obligation	53,200,000	53,200,000
Other miscellaneous contracts and leases [Member]
Commitments and Contingencies
Contractual obligation	$ 15,500,000	$ 15,500,000
Water pipeline commitment [Member]
Commitments and Contingencies
Water delivery commitments, remaining minimum contractual volumes | MMBbls	18	18
Minimum [Member] | Completion Service Commitment [Member]
Commitments and Contingencies
Potential Penalty for not Meeting Minimum Completion Service Arrangement Requirements	$ 0	$ 0
Minimum [Member] | Sand Sourcing Commitment [Member]
Commitments and Contingencies
Potential Penalty for not Meeting Minimum Sand Sourcing Requirements	0	0
Maximum [Member] | Completion Service Commitment [Member]
Commitments and Contingencies
Potential Penalty for not Meeting Minimum Completion Service Arrangement Requirements	13,400,000	13,400,000
Maximum [Member] | Sand Sourcing Commitment [Member]
Commitments and Contingencies
Potential Penalty for not Meeting Minimum Sand Sourcing Requirements	$ 10,000,000.0	$ 10,000,000.0