Note 16 - Pension and Postretirement Benefit Plans - Additional Information (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Net loss on settlement of pension plan | $ 17,377 | ||
| QDBP [Member] | |||
| Service cost | |||
| Interest cost | 1,589 | 1,640 | |
| Expected return on plan assets | (3,217) | (3,348) | |
| Amortization of prior service cost | |||
| Recognition of net actuarial loss | 1,913 | 391 | |
| Net loss on settlement of pension plan | 17,377 | ||
| Net periodic pension cost (benefit) | 17,662 | (1,317) | |
| SERP I and SERP II [Member] | |||
| Service cost | 61 | ||
| Interest cost | 184 | 184 | 177 |
| Amortization of prior service cost | 14 | ||
| Recognition of net actuarial loss | 57 | 63 | (33) |
| Net periodic pension cost (benefit) | 241 | 247 | 219 |
| Gain on curtailment | |||
| PRBP [Member] | |||
| Service cost | |||
| Interest cost | 17 | 18 | 29 |
| Recognition of net actuarial loss | 41 | 37 | 61 |
| Net periodic pension cost (benefit) | $ 58 | $ 55 | $ 90 |
| Discount Rate Used in the Calculation of Periodic Pension Costs | 3.90% | 3.70% | 4.60% |