Note 9 - Benefit Plans (Details Textual) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Deferred Compensation Liability, Current and Noncurrent | $ 3,100 | $ 3,100 | |
| Supplemental Executive Retirement Plan [Member] | |||
| Retirement Plan, Annual, Accrued Unfunded Contributions | 147 | 130 | |
| Other Postretirement Benefits Payable | 277 | 130 | |
| Pension Plan [Member] | |||
| Defined Contribution Plan, Employer Discretionary Contribution Amount | $ 168 | $ 149 | $ 134 |