Note 23 - Quarterly Financial Data (Unaudited) - Summary of Quarterly Earnings (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income	$ 28,746	$ 27,995	$ 27,786	$ 29,509	$ 23,370	$ 23,605	$ 24,382	$ 23,611	$ 114,036	$ 94,968	$ 98,294
Interest expense	1,029	1,161	1,447	1,827	1,313	1,384	1,393	1,425	5,464	5,515	7,449
Net interest income	27,717	26,834	26,339	27,682	22,057	22,221	22,989	22,186	108,572	89,453	90,845
Provision for loan losses	634	4,703	3,831	3,500	91	675	1,585	1,220	12,668	3,571	2,393
Net interest income after provision	27,083	22,131	22,508	24,182	21,966	21,546	21,404	20,966	95,904	85,882	88,452
Noninterest income, excluding net gain (loss) on sale of securities	7,733	7,638	6,913	7,164	9,314	7,634	8,692	8,080
Net gain (loss) on sale of securities	0	0	0	385	0	0	(43)	0	385	(43)	(618)
Noninterest expense	19,877	19,171	18,913	21,664	18,883	17,444	16,651	16,785	79,625	69,763	69,773
Income before income taxes	14,939	10,598	10,508	10,067	12,397	11,736	13,402	12,261	46,112	49,796	45,122
Income tax expense	3,389	2,332	2,270	2,195	2,833	2,580	2,951	2,630	10,186	10,994	8,782
Net income	$ 11,550	$ 8,266	$ 8,238	$ 7,872	$ 9,564	$ 9,156	$ 10,451	$ 9,631	$ 35,926	$ 38,802	$ 36,340
Basic (in dollars per share)	$ 0.65	$ 0.47	$ 0.47	$ 0.44	$ 0.61	$ 0.59	$ 0.67	$ 0.61	$ 2.02	$ 2.47	$ 2.19
Diluted (in dollars per share)	0.65	0.47	0.46	0.44	0.61	0.58	0.66	0.60	2.02	2.46	2.18
Dividends per common share (in dollars per share)	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.21	$ 1.00	$ 0.96	$ 0.78
Weighted average common shares outstanding, basic (in shares)	17,717,356	17,710,283	17,701,853	17,998,994	15,611,093	15,603,992	15,712,204	15,839,424	17,781,748	15,690,812	16,587,504
Weighted average diluted shares outstanding (in shares)	17,751,805	17,732,428	17,728,300	18,050,071	15,670,047	15,664,587	15,775,320	15,920,950	17,815,380	15,756,093	16,666,385