Note 5 - Allowances for Loan Losses - Past Due Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans receivable, total past due	$ 15,958	$ 19,987
Loans receivable, current	1,146,091	945,057
Loans receivable	1,162,049	965,044
Loans receivable greater than 90 days and accruing		302
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	1,113	1,060
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due		31
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due	14,845	18,896
Commercial Real Estate Portfolio Segment [Member]
Loans receivable, total past due	8,963	13,098
Loans receivable, current	424,341	365,421
Loans receivable	433,304	378,519
Loans receivable greater than 90 days and accruing
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, total past due
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due		9
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due	8,963	13,089
Construction and Land Development Portfolio Segment [Member]
Loans receivable, total past due
Loans receivable, current	104,617	61,453
Loans receivable	104,617	61,453
Loans receivable greater than 90 days and accruing
Construction and Land Development Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, total past due
Construction and Land Development Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due
Construction and Land Development Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due
Commercial Portfolio Segment [Member]
Loans receivable, total past due	3,864	3,719
Loans receivable, current	169,479	171,025
Loans receivable	173,343	174,744
Loans receivable greater than 90 days and accruing
Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	969	568
Commercial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due
Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due	2,895	3,151
Owner Occupied Real Estate [Member]
Loans receivable, total past due	2,136	2,186
Loans receivable, current	307,702	274,800
Loans receivable	309,838	276,986
Loans receivable greater than 90 days and accruing		172
Owner Occupied Real Estate [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, total past due		468
Owner Occupied Real Estate [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due
Owner Occupied Real Estate [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due	2,136	1,718
Consumer Portfolio Segment [Member]
Loans receivable, total past due	995	854
Loans receivable, current	75,188	62,806
Loans receivable	76,183	63,660
Loans receivable greater than 90 days and accruing
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	144	24
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due		22
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due	851	808
Residential Portfolio Segment [Member]
Loans receivable, total past due		130
Loans receivable, current	64,764	9,552
Loans receivable	64,764	9,682
Loans receivable greater than 90 days and accruing		130
Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, total past due
Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due
Residential Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due		$ 130