Annual report pursuant to Section 13 and 15(d)

Commitments Purchase Commitments (Details)

v3.3.1.900
Commitments Purchase Commitments (Details)
MMBTU / d in Thousands
Dec. 31, 2015
MMBTU / d
Other Commitments [Line Items]  
Sales Commitment, Volume 1,452
2016  
Other Commitments [Line Items]  
Sales Commitment, Volume 476
2017  
Other Commitments [Line Items]  
Sales Commitment, Volume 349
2018  
Other Commitments [Line Items]  
Sales Commitment, Volume 216
2019  
Other Commitments [Line Items]  
Sales Commitment, Volume 197
2020  
Other Commitments [Line Items]  
Sales Commitment, Volume 152
Thereafter  
Other Commitments [Line Items]  
Sales Commitment, Volume 62