Note 12 - Fair Value Measurements - Fair Value Adjustments for Assets Measured On a Nonrecurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net (increase) decrease in fair value:
Fair value adjustments	$ 232	$ 632	$ 447	$ 1,705
Impaired Loans [Member]
Net (increase) decrease in fair value:
Fair value adjustments	(3)	33	12	540
OREO [Member]
Net (increase) decrease in fair value:
Fair value adjustments	$ 235	$ 599	$ 435	$ 1,165