Nature of operations and summary of significant accounting policies (Unevaluated Oil and Natural Gas Properties) (Detail) - USD ($) $ in Thousands |
Mar. 31, 2017 |
Mar. 21, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|---|---|
| Capitalized costs of unproved properties excluded from amortization | ||||
| Leasehold acquisitions | $ 579,151 | |||
| Capitalized interest | 54 | |||
| Wells and facilities in progress of completion | 7,467 | |||
| Total unevaluated oil and natural gas properties excluded from amortization | $ 586,672 | $ 585,574 | ||
| Predecessor | ||||
| Capitalized costs of unproved properties excluded from amortization | ||||
| Leasehold acquisitions | $ 15,455 | |||
| Capitalized interest | 1,894 | |||
| Wells and facilities in progress of completion | 3,004 | |||
| Total unevaluated oil and natural gas properties excluded from amortization | $ 26,039 | $ 20,353 | $ 66,905 |