Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies (Firm Transportation Commitments) (Details)

v3.8.0.1
Commitments and Contingencies (Firm Transportation Commitments) (Details)
$ in Thousands
Mar. 31, 2018
USD ($)
MMBTU
Other Commitments [Line Items]  
Remaining 2018 | MMBTU 552,000
2019 | MMBTU 659,000
2020 | MMBTU 526,000
2021 | MMBTU 372,000
2022 | MMBTU 272,000
Thereafter | MMBTU 240,000
Total | MMBTU 2,621,000
Transportation commitment  
Other Commitments [Line Items]  
Remaining 2018 $ 186,036
2019 251,644
2020 247,581
2021 246,620
2022 246,620
Thereafter 2,511,853
Total 3,690,354
Purchase commitment  
Other Commitments [Line Items]  
Remaining 2018 $ 26,200