Note 12 - Fair Value Measurements - The Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Reported Value Measurement [Member]
Cash and cash equivalents, carrying amount	$ 127,575,000	$ 120,493,000
Held to maturity investment securities, carrying amount	3,572,000	3,611,000
Loans, net, carrying amount	941,570,000	948,960,000
Accrued interest receivable, carrying amount	4,519,000	5,392,000
Federal Home Loan Bank and Federal Reserve Bank Stock, carrying amount	9,840,000	9,368,000
Deposits, carrying amount	1,350,931,000	1,368,994,000
Federal funds purchased and other short-term borrowings, carrying amount	37,407,000	34,353,000
Securities sold under agreements to repurchase and other long-term borrowings, carrying amount	19,968,000	120,280,000
Subordinated notes payable to unconsolidated trusts, carrying amount	33,506,000	48,970,000
Accrued interest payable, carrying amount	322,000	851,000
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents, fair value	127,575,000	120,493,000
Held to maturity investment securities, fair value	3,801,000	3,809,000
Loans, net, fair value	933,104,000	945,809,000
Accrued interest receivable, fair value	4,519,000	5,392,000
Federal Home Loan Bank and Federal Reserve Bank Stock, fair value	0	0
Deposits, fair value	1,350,804,000	1,369,016,000
Federal funds purchased and other short-term borrowings, fair value	37,407,000	34,353,000
Securities sold under agreements to repurchase and other long-term borrowings, fair value	20,544,000	126,964,000
Subordinated notes payable to unconsolidated trusts, fair value	18,352,000	31,515,000
Accrued interest payable, fair value	322,000	851,000
Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents, fair value	127,575,000	120,493,000
Held to maturity investment securities, fair value	0	0
Loans, net, fair value	0	0
Accrued interest receivable, fair value	0	0
Federal Home Loan Bank and Federal Reserve Bank Stock, fair value	0	0
Deposits, fair value	1,067,178,000	1,043,616,000
Federal funds purchased and other short-term borrowings, fair value	0	0
Securities sold under agreements to repurchase and other long-term borrowings, fair value	0	0
Subordinated notes payable to unconsolidated trusts, fair value	0	0
Accrued interest payable, fair value	0	0
Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents, fair value	0	0
Held to maturity investment securities, fair value	3,801,000	3,809,000
Loans, net, fair value	0	0
Accrued interest receivable, fair value	4,519,000	5,392,000
Federal Home Loan Bank and Federal Reserve Bank Stock, fair value	0	0
Deposits, fair value	0	0
Federal funds purchased and other short-term borrowings, fair value	37,407,000	34,353,000
Securities sold under agreements to repurchase and other long-term borrowings, fair value	20,544,000	126,964,000
Subordinated notes payable to unconsolidated trusts, fair value	0	0
Accrued interest payable, fair value	322,000	851,000
Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents, fair value	0	0
Held to maturity investment securities, fair value	0	0
Loans, net, fair value	933,104,000	945,809,000
Accrued interest receivable, fair value	0	0
Federal Home Loan Bank and Federal Reserve Bank Stock, fair value	0	0
Deposits, fair value	283,626,000	325,400,000
Federal funds purchased and other short-term borrowings, fair value	0	0
Securities sold under agreements to repurchase and other long-term borrowings, fair value	0	0
Subordinated notes payable to unconsolidated trusts, fair value	18,352,000	31,515,000
Accrued interest payable, fair value	0	0
Cash and cash equivalents, carrying amount	127,575,000	120,493,000	$ 107,855,000	$ 100,914,000
Held to maturity investment securities, carrying amount	3,572,000	3,611,000
Held to maturity investment securities, fair value	3,801,000	3,809,000
Loans, net, carrying amount	941,570,000	948,960,000
Deposits, carrying amount	1,350,931,000	1,368,994,000
Federal funds purchased and other short-term borrowings, carrying amount	37,407,000	34,353,000
Securities sold under agreements to repurchase and other long-term borrowings, carrying amount	19,968,000	120,280,000
Subordinated notes payable to unconsolidated trusts, carrying amount	$ 33,506,000	$ 48,970,000