Note 26 - Quarterly Operating Results (Unaudited) - Quarterly Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest income	$ 26,368	$ 25,942	$ 25,162	$ 24,700	$ 24,039	$ 23,284	$ 23,000	$ 22,847	$ 22,778	$ 22,692	$ 22,013	$ 21,604	$ 102,172	$ 93,170	$ 89,087
Interest expense	1,293	1,182	1,212	1,231	1,217	1,203	1,199	1,233	1,267	1,329	1,358	1,376	4,918	4,852	5,330
Net interest income	25,075	24,760	23,950	23,469	22,822	22,081	21,801	21,614	21,511	21,363	20,655	20,228	97,254	88,318	83,757
Provision for loan losses	500	1,250	750	500	750					(2,100)	1,350	350	3,000	750	(400)
Net interest income after provision	24,575	23,510	23,200	22,969	22,072	22,081	21,801	21,614	21,511	23,463	19,305	19,878	94,254	87,568	84,157
Non-interest income	11,319	11,358	10,778	10,082	10,073	9,985	10,219	9,673	9,773	9,850	10,057	9,475	43,537	39,950	39,155
Non-interest expenses	21,269	20,518	20,193	19,540	18,322	18,430	18,867	17,779	19,255	18,709	17,701	17,544	81,520	73,398	73,209
Income before income taxes	14,625	14,350	13,785	13,511	13,823	13,636	13,153	13,508	12,029	14,604	11,661	11,809	56,271	54,120	50,103
Income tax expense	4,009	3,883	3,676	3,676	4,177	4,352	4,151	4,253	3,307	4,715	3,627	3,632	$ 15,244	$ 16,933	$ 15,281
Net income	$ 10,616	$ 10,467	$ 10,109	$ 9,835	$ 9,646	$ 9,284	$ 9,002	$ 9,255	$ 8,722	$ 9,889	$ 8,034	$ 8,177
Basic earnings per share (in dollars per share)	$ 0.47	$ 0.47	$ 0.45	$ 0.44	$ 0.43	$ 0.42	$ 0.41	$ 0.42	$ 0.40	$ 0.45	$ 0.37	$ 0.37	$ 1.84	$ 1.68	$ 1.59
Diluted earnings per share (in dollars per share)	$ 0.46	$ 0.46	$ 0.45	$ 0.44	$ 0.43	$ 0.41	$ 0.40	$ 0.42	$ 0.39	$ 0.45	$ 0.37	$ 0.37	$ 1.80	$ 1.65	$ 1.57