Note 18 - Segments - Financial Information by Business Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Net interest income	$ 32,446	$ 29,684
Provision for credit losses	5,550	600
Non-interest income	6,218	5,439
All other non-interest income	6,318	5,569
Non-interest expenses	23,950	22,612
Income before income tax expense	15,482	17,480
Income tax expense	2,250	1,839
Net income	13,232	15,641
Segment assets	3,784,586	3,281,016	$ 3,724,197
Commercial Banking [Member]
Net interest income	32,361	29,608
Provision for credit losses	5,550	600
Non-interest income	0	0
All other non-interest income	6,318	5,569
Non-interest expenses	20,638	19,579
Income before income tax expense	12,491	14,998
Income tax expense	1,601	1,300
Net income	10,890	13,698
Segment assets	3,781,063	3,277,415
Investment Management and Trust [Member]
Net interest income	85	76
Provision for credit losses	0	0
Non-interest income	6,218	5,439
All other non-interest income	0	0
Non-interest expenses	3,312	3,033
Income before income tax expense	2,991	2,482
Income tax expense	649	539
Net income	2,342	1,943
Segment assets	$ 3,523	$ 3,601