Statement of Cash Flows - Supplemental Information (Schedule of Supplemental Cash Paid and Non-cash Transactions) (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Supplemental Cash Flow Information [Abstract] | |||
| Cash paid for interest, net of capitalized amounts | $ 26,859 | $ 24,632 | $ 7,341 |
| Non-cash transactions: | |||
| Capital expenditures (excluded from) included in accounts payable and accrued drilling costs | (26,228) | 12,777 | 582 |
| Capital expenditures included in accounts receivable | 4,077 | (4,077) | |
| Asset retirement obligation included in oil and natural gas properties | 526 | 221 | (1,302) |
| Asset retirement obligation for property disposals | (416) | (645) | (4,354) |
| Application of advances to operators | 11,445 | 58,326 | 19,755 |
| Other | $ 5 | $ (11) | $ 47 |