Note 8 - Commitments and Off-balance Sheet Risk (Details) - Exposure to Credit Losses - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Note 8 - Commitments and Off-balance Sheet Risk (Details) - Exposure to Credit Losses [Line Items]
Contractual amounts of financial instruments with off-balance sheet risk	$ 839,429,000	$ 821,738,000
Loan Origination Commitments [Member]
Note 8 - Commitments and Off-balance Sheet Risk (Details) - Exposure to Credit Losses [Line Items]
Contractual amounts of financial instruments with off-balance sheet risk	218,392,000	178,034,000
Standby Letters of Credit [Member]
Note 8 - Commitments and Off-balance Sheet Risk (Details) - Exposure to Credit Losses [Line Items]
Contractual amounts of financial instruments with off-balance sheet risk	33,567,000	34,946,000
Commercial Portfolio Segment [Member] | Unused lines of Credit [Member]
Note 8 - Commitments and Off-balance Sheet Risk (Details) - Exposure to Credit Losses [Line Items]
Contractual amounts of financial instruments with off-balance sheet risk	501,735,000	522,658,000
1-4 Family Mortgages [Member] | Unused lines of Credit [Member]
Note 8 - Commitments and Off-balance Sheet Risk (Details) - Exposure to Credit Losses [Line Items]
Contractual amounts of financial instruments with off-balance sheet risk	62,364,000	61,905,000
Consumer Portfolio Segment [Member] | Unused lines of Credit [Member]
Note 8 - Commitments and Off-balance Sheet Risk (Details) - Exposure to Credit Losses [Line Items]
Contractual amounts of financial instruments with off-balance sheet risk	16,874,000	15,612,000
Consumer Other Financing Receivable 1 [Member] | Unused lines of Credit [Member]
Note 8 - Commitments and Off-balance Sheet Risk (Details) - Exposure to Credit Losses [Line Items]
Contractual amounts of financial instruments with off-balance sheet risk	$ 6,497,000	$ 8,583,000