Asset Retirement Obligations (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | ||
| Asset retirement obligations, beginning of period | $ 13,895 | $ 12,161 |
| Liabilities incurred | 1,393 | 1,535 |
| Liabilities acquired | 1,167 | 165 |
| Liabilities settled | (1,361) | (673) |
| Accretion expense | 912 | 791 |
| Revisions to estimated cash flows | 868 | (84) |
| Asset retirement obligations, end of period | $ 16,874 | $ 13,895 |