Note 9 - Fair Value Measurements and Disclosures (Details) - Estimated Fair Values and Carrying Amounts of Financial and Off-Balance Sheet Instruments (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Financial assets
Cash and cash equivalents	$ 22,341,000	$ 16,286,000	$ 20,620,000	$ 15,453,000
Trading	4,485,000	0
Investment securities available-for-sale	359,452,000	388,670,000
Investment securities held-to-maturity	146,000	146,000
Investment securities held-to-maturity	161,000	162,000
Restricted investment in bank stocks	1,764,000	1,764,000
Net loans	513,037,000	492,791,000
Mortgage servicing rights	509,000	519,000
Accrued interest receivable	2,602,000	2,579,000
Financial liabilities
Deposits with no stated maturities	814,234,000	814,532,000
Short-term borrowings	32,935,000	35,156,000
Long-term debt	5,000,000	5,000,000
Accrued interest payable	374,000	392,000
With No Stated Maturities [Member] | Estimate of Fair Value Measurement [Member]
Financial liabilities
Deposits with no stated maturities	575,163,000	574,987,000
With No Stated Maturities [Member] | Fair Value, Inputs, Level 1 [Member]
Financial liabilities
Deposits with no stated maturities	575,163,000	574,987,000
With No Stated Maturities [Member]
Financial liabilities
Deposits with no stated maturities	575,163,000	574,987,000
With Stated Maturities [Member] | Estimate of Fair Value Measurement [Member]
Financial liabilities
Deposits with no stated maturities	241,015,000	241,959,000
With Stated Maturities [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities
Deposits with no stated maturities	241,015,000	241,959,000
With Stated Maturities [Member]
Financial liabilities
Deposits with no stated maturities	239,071,000	239,545,000
Estimate of Fair Value Measurement [Member]
Financial assets
Cash and cash equivalents	22,341,000	16,286,000
Trading	4,485,000
Investment securities available-for-sale	359,452,000	388,670,000
Investment securities held-to-maturity	161,000	162,000
Restricted investment in bank stocks	1,764,000	1,764,000
Net loans	513,395,000	491,635,000
Mortgage servicing rights	630,000	643,000
Accrued interest receivable	2,602,000	2,579,000
Financial liabilities
Short-term borrowings	32,935,000	35,156,000
Long-term debt	5,000,000	5,056,000
Accrued interest payable	374,000	392,000
Fair Value, Inputs, Level 1 [Member]
Financial assets
Cash and cash equivalents	22,341,000	16,286,000
Investment securities available-for-sale	6,743,000	6,625,000
Restricted investment in bank stocks	1,764,000	1,764,000
Financial liabilities
Short-term borrowings	32,935,000	35,156,000
Fair Value, Inputs, Level 2 [Member]
Financial assets
Trading	4,485,000
Investment securities available-for-sale	350,471,000	379,976,000
Investment securities held-to-maturity	161,000	162,000
Accrued interest receivable	2,602,000	2,579,000
Financial liabilities
Long-term debt	5,000,000	5,056,000
Accrued interest payable	374,000	392,000
Fair Value, Inputs, Level 3 [Member]
Financial assets
Investment securities available-for-sale	2,238,000	2,069,000
Net loans	513,395,000	491,635,000
Mortgage servicing rights	$ 630,000	$ 643,000