Note 3 - Accumulated Other Comprehensive (Loss) Income - Amounts Reclassified Out of Accumulated Other Comprehensive (Loss) Income by Component (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income tax expense	$ (1,303)	$ (1,722)	$ (2,463)	$ (2,998)
Net income	5,847	4,482	11,488	7,811
Salaries and employee benefits	(7,410)	(7,475)	(14,900)	(15,335)
Total before tax	7,150	6,204	13,951	10,809
Reclassification out of Accumulated Other Comprehensive Income [Member]
Net income	1	(2)	2	(58)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Unrealized gains (losses) on available for sale investment securities		(1)		(10)
Income tax expense				3
Net income		(1)		(7)
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)
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	(2)	2	(3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Income tax expense		1		27
Net income	1	(1)	2	(51)
Total before tax	$ 1	$ (2)	$ 2	$ (78)