Note 8 - Loans - Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Balance	$ 122,651	$ 121,899	$ 122,391	$ 123,279
Provision/(reversal) for possible credit losses	(2,000)	(1,500)	(2,000)	(4,500)
Charge-offs	(3,356)	(122)	(6,300)	(1,019)
Recoveries	8,613	3,180	11,817	5,697
Net (charge-offs)/recoveries	5,257	3,058	5,517	4,678
Balance	125,908	123,457	125,908	123,457
Reserve for impaired loans	1,501	3,704	1,501	3,704
Reserve for non-impaired loans	124,407	119,753	124,407	119,753
Reserve for off-balance sheet credit commitments	4,550	3,088	4,550	3,088
Commercial Portfolio Segment [Member]
Balance	54,293	55,179	54,978	49,796
Provision/(reversal) for possible credit losses	7,400	1,270	8,262	6,097
Charge-offs	(3,356)	(122)	(6,300)	(629)
Recoveries	212	187	1,609	1,250
Net (charge-offs)/recoveries	(3,144)	65	(4,691)	621
Balance	58,549	56,514	58,549	56,514
Reserve for impaired loans	744	2,506	744	2,506
Reserve for non-impaired loans	57,805	54,008	57,805	54,008
Reserve for off-balance sheet credit commitments	2,505	1,615	2,505	1,615
Real Estate Construction Portfolio Segment [Member]
Balance	21,010	20,663	19,626	24,838
Provision/(reversal) for possible credit losses	(2,690)	519	(2,540)	(3,744)
Charge-offs	0	0	0	0
Recoveries	3,378	44	4,612	132
Net (charge-offs)/recoveries	3,378	44	4,612	132
Balance	21,698	21,226	21,698	21,226
Reserve for impaired loans	0	0	0	0
Reserve for non-impaired loans	21,698	21,226	21,698	21,226
Reserve for off-balance sheet credit commitments	1,608	1,174	1,608	1,174
Commercial Real Estate Portfolio Segment [Member]
Balance	33,154	33,976	33,487	37,610
Provision/(reversal) for possible credit losses	(4,648)	(4,138)	(5,234)	(8,672)
Charge-offs	0	0	0	(390)
Recoveries	4,961	2,944	5,214	4,234
Net (charge-offs)/recoveries	4,961	2,944	5,214	3,844
Balance	33,467	32,782	33,467	32,782
Reserve for impaired loans	536	917	536	917
Reserve for non-impaired loans	32,931	31,865	32,931	31,865
Reserve for off-balance sheet credit commitments	121	78	121	78
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Balance	14,164	12,062	14,282	11,013
Provision/(reversal) for possible credit losses	(2,057)	842	(2,495)	1,815
Charge-offs	0	0	0	0
Recoveries	62	5	382	81
Net (charge-offs)/recoveries	62	5	382	81
Balance	12,169	12,909	12,169	12,909
Reserve for impaired loans	221	281	221	281
Reserve for non-impaired loans	11,948	12,628	11,948	12,628
Reserve for off-balance sheet credit commitments	313	215	313	215
Installment and Other Loans [Member ]
Balance	30	19	18	22
Provision/(reversal) for possible credit losses	(5)	7	7	4
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Net (charge-offs)/recoveries	0	0	0	0
Balance	25	26	25	26
Reserve for impaired loans	0	0	0	0
Reserve for non-impaired loans	25	26	25	26
Reserve for off-balance sheet credit commitments	$ 3	$ 6	$ 3	$ 6