Note 12 - Pension and Other Postretirement Benefit Plans (Details) - Amounts Recognized in Accumulated Other Comprehensive Income, on a Pre-Tax Basis - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Note 12 - Pension and Other Postretirement Benefit Plans (Details) - Amounts Recognized in Accumulated Other Comprehensive Income, on a Pre-Tax Basis [Line Items]
Net Actuarial loss (gain)	$ 9,323	$ 11,580	$ 5,608
Prior Service cost (credit)	(447)	(492)	(537)
Total	8,876	11,088	5,071
Retirement Plan [Member]
Note 12 - Pension and Other Postretirement Benefit Plans (Details) - Amounts Recognized in Accumulated Other Comprehensive Income, on a Pre-Tax Basis [Line Items]
Net Actuarial loss (gain)	8,589	9,938	5,899
Total	8,589	9,938	5,899
Other Postretirement Benefit Plan [Member]
Note 12 - Pension and Other Postretirement Benefit Plans (Details) - Amounts Recognized in Accumulated Other Comprehensive Income, on a Pre-Tax Basis [Line Items]
Net Actuarial loss (gain)	1,296	2,130	205
Prior Service cost (credit)	(538)	(623)	(708)
Total	758	1,507	(503)
Directors' Plan [Member]
Note 12 - Pension and Other Postretirement Benefit Plans (Details) - Amounts Recognized in Accumulated Other Comprehensive Income, on a Pre-Tax Basis [Line Items]
Net Actuarial loss (gain)	(562)	(488)	(496)
Prior Service cost (credit)	91	131	171
Total	$ (471)	$ (357)	$ (325)