Derivative and Hedging Financial Instruments - Summary of Volumes and Average Contract Prices of Contracts (Detail)
|
Dec. 31, 2015
MMBTU
$ / MMBTU
|
Dec. 23, 2014
$ / MMBTU
|
Aug. 20, 2014
$ / MMBTU
|
| Morgan Stanley Restrike [Member] |
|
|
|
| Derivative [Line Items] |
|
|
|
| Volumes (MMBtu) | MMBTU |
10,263,943
|
|
|
| Commodity contracts, Basis Swap Fixed Price/mmbtu | $ / MMBTU |
|
|
(3.92)
|
| Morgan Stanley Restrike [Member] | 2016 [Member] |
|
|
|
| Derivative [Line Items] |
|
|
|
| Volumes (MMBtu) | MMBTU |
4,166,789
|
|
|
| Commodity contracts, Weighted- Average Fixed Price/mmbtu | $ / MMBTU |
3.27
|
|
|
| Morgan Stanley Restrike [Member] | 2017 [Member] |
|
|
|
| Derivative [Line Items] |
|
|
|
| Volumes (MMBtu) | MMBTU |
3,300,403
|
|
|
| Commodity contracts, Weighted- Average Fixed Price/mmbtu | $ / MMBTU |
3.27
|
|
|
| Morgan Stanley Restrike [Member] | 2018 [Member] |
|
|
|
| Derivative [Line Items] |
|
|
|
| Volumes (MMBtu) | MMBTU |
2,796,751
|
|
|
| Commodity contracts, Weighted- Average Fixed Price/mmbtu | $ / MMBTU |
3.27
|
|
|
| Morgan Stanley Fixed III [Member] |
|
|
|
| Derivative [Line Items] |
|
|
|
| Volumes (MMBtu) | MMBTU |
4,747,755
|
|
|
| Commodity contracts, Basis Swap Fixed Price/mmbtu | $ / MMBTU |
|
(1.12)
|
|
| Morgan Stanley Fixed III [Member] | 2016 [Member] |
|
|
|
| Derivative [Line Items] |
|
|
|
| Volumes (MMBtu) | MMBTU |
1,878,290
|
|
|
| Commodity contracts, Basis Swap Fixed Price/mmbtu | $ / MMBTU |
(1.12)
|
|
|
| Morgan Stanley Fixed III [Member] | 2017 [Member] |
|
|
|
| Derivative [Line Items] |
|
|
|
| Volumes (MMBtu) | MMBTU |
1,539,998
|
|
|
| Commodity contracts, Basis Swap Fixed Price/mmbtu | $ / MMBTU |
(1.12)
|
|
|
| Morgan Stanley Fixed III [Member] | 2018 [Member] |
|
|
|
| Derivative [Line Items] |
|
|
|
| Volumes (MMBtu) | MMBTU |
1,329,467
|
|
|
| Commodity contracts, Basis Swap Fixed Price/mmbtu | $ / MMBTU |
(1.12)
|
|
|