Note 12 - Pension and Other Postretirement Benefit Plans - Assumptions Used to Develop Periodic Pension Benefit for the Retirement Plan (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Weighted average discount rate	4.06%	3.76%	4.60%
Rate of increase in future compensation levels	0.00%	0.00%	0.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	0.00%	0.00%	0.00%
Retirement Plan [Member]
Weighted average discount rate	4.06%	3.76%	4.60%
Rate of increase in future compensation levels	0.00%	0.00%	0.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets	7.25%	7.50%	7.50%