Note 26 - Quarterly Operating Results (Unaudited) - Quarterly Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest income	$ 37,795	$ 37,973	$ 36,968	$ 35,029	$ 35,004	$ 33,021	$ 32,004	$ 29,744	$ 29,098	$ 28,120	$ 27,026	$ 26,655	$ 147,765	$ 129,773	$ 110,899
Interest expense	5,075	5,903	6,194	5,372	5,092	4,500	3,330	2,435	2,069	1,947	1,781	1,449	22,544	15,357	7,246
Net interest income	32,720	32,070	30,774	29,657	29,912	28,521	28,674	27,309	27,029	26,173	25,245	25,206	125,221	114,416	103,653
Provision for loan and lease losses	0	400	0	600	0	735	1,235	735	900	150	600	900	1,000	2,705	2,550
Net interest income after provision	32,720	31,670	30,774	29,057	29,912	27,786	27,439	26,574	26,129	26,023	24,645	24,306	124,221	111,711	101,103
Non-interest income	13,161	13,304	12,263	11,062	11,576	11,426	11,435	10,909	11,407	10,945	11,525	10,622	49,790	45,346	44,499
Non-interest expenses	26,291	23,957	25,464	22,639	24,565	21,781	22,136	21,027	27,048	21,168	21,209	20,995	98,351	89,509	90,420
Income before income taxes and equity in undistributed net income of subsidiary	19,590	21,017	17,573	17,480	16,923	17,431	16,738	16,456	10,488	15,800	14,961	13,933	75,660	67,548	55,182
Income tax benefit	2,941	3,783	1,030	1,839	2,265	3,555	3,159	3,052	5,542	4,096	4,359	3,142	9,593	12,031	17,139
Net income	$ 16,649	$ 17,234	$ 16,543	$ 15,641	$ 14,658	$ 13,876	$ 13,579	$ 13,404	$ 4,946	$ 11,704	$ 10,602	$ 10,791	$ 66,067	$ 55,517	$ 38,043
Basic earnings per share (in dollars per share)	$ 0.74	$ 0.76	$ 0.73	$ 0.69	$ 0.65	$ 0.61	$ 0.60	$ 0.59	$ 0.22	$ 0.52	$ 0.47	$ 0.48	$ 2.92	$ 2.45	$ 1.69
Diluted earnings per share (in dollars per share)	$ 0.73	$ 0.76	$ 0.72	$ 0.68	$ 0.64	$ 0.60	$ 0.59	$ 0.58	$ 0.22	$ 0.51	$ 0.46	$ 0.47	$ 2.89	$ 2.42	$ 1.66