Note 3 - Accumulated Other Comprehensive Income - Amounts Reclassified Out of Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Investment securities gains, net	$ (9)	$ 83
Income tax expense	(1,276)	(2,715)
Net income	3,329	6,180
Salaries and employee benefits	(7,617)	(7,979)
Total before tax	4,605	8,895
Reclassification out of Accumulated Other Comprehensive Income [Member]
Net income	(55)	45
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Investment securities gains, net	(9)	83
Income tax expense	3	(29)
Net income	(6)	54
Total before tax	(76)	(14)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Salaries and employee benefits	(75)	(13)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Salaries and employee benefits	(1)	(1)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Income tax expense	27	5
Net income	$ (49)	$ (9)