Note 6 - Loans Receivable and Allowance for Loan Losses - Past Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loans receivable, total past due	$ 15,062	$ 15,958
Loans receivable, current	1,302,377	1,146,091
Loans receivable	1,317,439	1,162,049
Loans receivable greater than 90 days and accruing
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, total past due	827	1,113
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	129
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due	14,106	14,845
Commercial Real Estate Portfolio Segment [Member]
Loans receivable, total past due	8,370	8,963
Loans receivable, current	481,204	424,341
Loans receivable	489,574	433,304
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	815
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due	129
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due	7,426	8,963
Construction and Land Development Portfolio Segment [Member]
Loans receivable, total past due
Loans receivable, current	120,165	104,617
Loans receivable	120,165	104,617
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	3,885	3,864
Loans receivable, current	184,369	169,479
Loans receivable	188,254	173,343
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
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	3,885	2,895
Owner Occupied Real Estate [Member]
Loans receivable, total past due	2,004	2,136
Loans receivable, current	333,867	307,702
Loans receivable	335,871	309,838
Loans receivable greater than 90 days and accruing
Owner Occupied Real Estate [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans receivable, total past due
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	2,004	2,136
Consumer Portfolio Segment [Member]
Loans receivable, total past due	803	995
Loans receivable, current	82,664	75,188
Loans receivable	83,467	76,183
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	12	144
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans receivable, total past due
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans receivable, total past due	791	851
Residential Portfolio Segment [Member]
Loans receivable, total past due
Loans receivable, current	100,108	64,764
Loans receivable	100,108	64,764
Loans receivable greater than 90 days and accruing
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