Note 6 - Comprehensive Income (Details) - Amounts Reclassified Out of Accumulated Other Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax effect	$ (715)	$ (580)	$ (1,999)	$ (1,913)
Total reclass out of accumulated other comprehensive income, net of tax	2,220	2,044	6,290	6,512
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized net holding gains on available-for-sale securities	83	180	800	1,087
Tax effect	(29)	(61)	(273)	(370)
Total reclass out of accumulated other comprehensive income, net of tax	$ 54	$ 119	$ 527	$ 717