Note 20 - Segments - Financial Information by Business Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Non-interest expense	$ 21,346	$ 20,193	$ 42,494	$ 39,733
Income before income taxes	14,961	13,785	28,894	27,296
Income tax expense	4,359	3,676	7,501	7,352
Net income	10,602	10,109	21,393	19,944
Segment assets	3,126,762	2,909,519	3,126,762	2,909,519	$ 3,039,481
Net interest income	25,232	23,950	50,416	47,419
Provision for loan losses	600	750	1,500	1,250	$ 3,000
Wealth management and trust services	5,153	4,807	10,247	9,419
All other non-interest income	6,522	5,971	12,225	11,441
Commercial Banking [Member]
Non-interest expense	18,164	17,297	36,265	34,192
Income before income taxes	12,910	11,812	24,719	23,294
Income tax expense	3,626	2,971	6,010	5,922
Net income	9,284	8,841	18,709	17,372
Segment assets	3,124,522	2,907,393	3,124,522	2,907,393
Net interest income	25,152	23,888	50,259	47,295
Provision for loan losses	600	750	1,500	1,250
Wealth management and trust services
All other non-interest income	6,522	5,971	12,225	11,441
Investment Management and Trust [Member]
Non-interest expense	3,182	2,896	6,229	5,541
Income before income taxes	2,051	1,973	4,175	4,002
Income tax expense	733	705	1,491	1,430
Net income	1,318	1,268	2,684	2,572
Segment assets	2,240	2,126	2,240	2,126
Net interest income	80	62	157	124
Provision for loan losses
Wealth management and trust services	5,153	4,807	10,247	9,419
All other non-interest income