Note 12 - Pension and Other Postretirement Benefit Plans (Details) - The Resulting Net Periodic Postretirement Expense Consisted of the Following Components for the Year - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Note 12 - Pension and Other Postretirement Benefit Plans (Details) - The Resulting Net Periodic Postretirement Expense Consisted of the Following Components for the Year [Line Items]
Amortization of prior service credit	$ (26)	$ (26)	$ (26)
Postretirement Plans [Member]
Note 12 - Pension and Other Postretirement Benefit Plans (Details) - The Resulting Net Periodic Postretirement Expense Consisted of the Following Components for the Year [Line Items]
Service cost	382	358	449
Interest cost	300	253	219
Amortization of unrecognized loss	119		50
Amortization of past service credit	(85)	(85)	(85)
Net postretirement benefit expense	716	526	633
Current year actuarial (gain) loss	(715)	1,925	(943)
Amortization of actuarial loss	(119)		(50)
Amortization of prior service credit	85	85	85
Total recognized in other comprehensive income	(749)	2,010	(908)
Total recognized in net postretirement expense and other comprehensive income	$ (33)	$ 2,536	$ (275)