Asset retirement obligations (Detail) - USD ($)
$ in Thousands |
|
3 Months Ended |
12 Months Ended |
Mar. 31, 2017 |
Mar. 21, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
| Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] |
|
|
|
|
| Liability for asset retirement obligations, Beginning balance |
$ 70,476
|
|
|
|
| Accretion expense |
121
|
|
|
|
| Liability for asset retirement obligations, Ending balance |
70,597
|
$ 70,476
|
|
|
| Less current portion included in accounts payable and accrued liabilities |
6,066
|
|
|
|
| Fair value fresh-start adjustment |
|
(2,757)
|
|
|
| Asset retirement obligations, long-term |
64,531
|
64,216
|
|
|
| Predecessor |
|
|
|
|
| Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] |
|
|
|
|
| Liability for asset retirement obligations, Beginning balance |
$ 73,233
|
72,137
|
$ 48,612
|
$ 47,424
|
| Liabilities incurred in current period |
|
535
|
3,918
|
1,861
|
| Liabilities settled and disposed in current period |
|
(869)
|
(2,729)
|
(6,472)
|
| Revisions in estimated cash flows |
|
181
|
18,364
|
2,139
|
| Accretion expense |
|
1,249
|
3,972
|
3,660
|
| Liability for asset retirement obligations, Ending balance |
|
73,233
|
72,137
|
48,612
|
| Less current portion included in accounts payable and accrued liabilities |
|
|
6,681
|
2,178
|
| Asset retirement obligations, long-term |
|
$ 66,973
|
65,456
|
46,434
|
| Cash in escrow |
|
|
$ 1,519
|
$ 1,567
|