Note 16 - Pension and Postretirement Benefit Plans (Details Textual) |
12 Months Ended | |||
|---|---|---|---|---|
|
Dec. 31, 2016
USD ($)
|
Dec. 31, 2015
USD ($)
|
Dec. 31, 2014
USD ($)
|
Dec. 31, 2005 |
|
| Number of Defined Benefit Pension Plans | 3 | |||
| Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements | $ (17,377,000) | |||
| Deferred Compensation Plan Assets | $ 169,000 | |||
| Percentage of Fair Value to Total Pension Plan Asset | 10.00% | |||
| QDBP [Member] | ||||
| Defined Benefit Plan Employee Eligible Age | 20.5 | |||
| Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements | $ (17,377,000) | |||
| SERP I and SERP II [Member] | ||||
| Number of Defined Benefit Pension Plans | 2 | |||
| Defined Benefit Plan, Participants Amounts Frozen, Percentage | 20.00% | |||
| Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year | $ 259 | |||
| PRBP [Member] | ||||
| Defined Benefit Plan, Maximum Annual Payment, Percentage | 120.00% | |||