Note 12 - Asset Retirement Obligations and Environmental Reserves (Details) - Asset Retirement Obligations - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Asset Retirement Obligations [Abstract] | ||
| Beginning balance | $ 796 | $ 771 |
| Accretion expense | 26 | 25 |
| Balance at December 31 | $ 822 | $ 796 |