Note 12 - Fair Value Measurements - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets
Held to maturity investment securities	$ 3,597	$ 3,597
Reported Value Measurement [Member]
Assets
Cash and cash equivalents	117,608	113,534
Held to maturity investment securities	3,448	3,488
Loans, net	986,063	961,631
Accrued interest receivable	4,695	5,019
Federal Home Loan Bank and Federal Reserve Bank Stock	13,235	9,840
Liabilities
Deposits	1,361,824	1,369,907
Securities sold under agreements to repurchase	35,537	36,370
Federal Home Loan Bank advances	3,521	18,646
Subordinated notes payable to unconsolidated trusts	33,506	33,506
Accrued interest payable	344	321
Estimate of Fair Value Measurement [Member]
Assets
Cash and cash equivalents	117,608	113,534
Held to maturity investment securities	3,597	3,597
Loans, net	976,344	962,437
Accrued interest receivable	4,695	5,019
Federal Home Loan Bank and Federal Reserve Bank Stock	13,235	9,840
Liabilities
Deposits	1,361,653	1,369,567
Securities sold under agreements to repurchase	35,542	36,381
Federal Home Loan Bank advances	3,608	19,114
Subordinated notes payable to unconsolidated trusts	21,142	21,234
Accrued interest payable	344	321
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Cash and cash equivalents	117,608	113,534
Held to maturity investment securities	0	0
Loans, net	0	0
Accrued interest receivable	0	0
Federal Home Loan Bank and Federal Reserve Bank Stock	0	0
Liabilities
Deposits	1,128,645	1,099,211
Securities sold under agreements to repurchase	0	0
Federal Home Loan Bank advances	0	0
Subordinated notes payable to unconsolidated trusts	0	0
Accrued interest payable	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Cash and cash equivalents	0	0
Held to maturity investment securities	3,597	3,597
Loans, net	0	0
Accrued interest receivable	4,695	5,019
Federal Home Loan Bank and Federal Reserve Bank Stock	0	0
Liabilities
Deposits	0	0
Securities sold under agreements to repurchase	35,542	36,381
Federal Home Loan Bank advances	3,608	19,114
Subordinated notes payable to unconsolidated trusts	0	0
Accrued interest payable	344	321
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Held to maturity investment securities	0	0
Loans, net	976,344	962,437
Accrued interest receivable	0	0
Federal Home Loan Bank and Federal Reserve Bank Stock	13,235	9,840
Liabilities
Deposits	233,008	270,356
Securities sold under agreements to repurchase	0	0
Federal Home Loan Bank advances	0	0
Subordinated notes payable to unconsolidated trusts	21,142	21,234
Accrued interest payable	$ 0	$ 0