Note 20 - Segments - Financial Information by Business Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Net interest income	$ 29,657	$ 27,309
Provision	600	735
Non-interest income	5,439	5,500
All other non-interest income	5,623	5,409
Non-interest expenses	22,639	21,027
Income before income tax expense	17,480	16,456
Income tax expense	1,839	3,052
Net income	15,641	13,404
Segment assets	3,281,016	3,285,480	$ 3,302,924
Commercial Banking [Member]
Net interest income	29,581	27,238
Provision	600	735
Non-interest income
All other non-interest income	5,623	5,409
Non-interest expenses	19,606	17,829
Income before income tax expense	14,998	14,083
Income tax expense	1,300	2,537
Net income	13,698	11,546
Segment assets	3,279,248	3,283,539
Investment Management and Trust [Member]
Net interest income	76	71
Provision
Non-interest income	5,439	5,500
All other non-interest income
Non-interest expenses	3,033	3,198
Income before income tax expense	2,482	2,373
Income tax expense	539	515
Net income	1,943	1,858
Segment assets	$ 1,768	$ 1,941