Note 9 - Fair Value Measurements and Disclosures (Details) - Estimated Fair Values and Carrying Amounts of Financial and Off-Balance Sheet Instruments (USD $)	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
Financial assets
Cash and cash equivalents, carrying amount	$ 15,897,000	$ 15,453,000	$ 20,263,000	$ 10,555,000
Cash and cash equivalents, fair value	15,897,000	15,453,000
Investment securities available-for-sale	380,364,000	401,502,000
Investment securities held-to-maturity, carrying amount	146,000	146,000
Investment securities held-to-maturity, fair value	163,000	166,000
Restricted investment in bank stocks, carrying amount	1,837,000	2,244,000
Restricted investment in bank stocks, fair value	1,837,000	2,244,000
Loans held-for-sale, carrying amount	1,328,000	1,616,000
Loans held-for-sale, fair value	1,328,000	1,674,000
Net loans, carrying amount	479,784,000	467,961,000
Net loans, fair value	481,469,000	474,330,000
Mortgage servicing rights, carrying amount	504,000	448,000
Mortgage servicing rights, fair value	576,000	464,000
Accrued interest receivable, carrying amount	2,981,000	2,803,000
Accrued interest receivable, fair value	2,981,000	2,803,000
Financial liabilities
Deposits, carrying amount	795,913,000	801,638,000
Short-term borrowings, carrying amount	32,851,000	32,488,000
Short-term borrowings, fair value	32,851,000	32,488,000
Long-term debt, carrying amount	5,282,000	5,287,000
Long-term debt, fair value	5,412,000	5,694,000
Accrued interest payable, carrying amount	407,000	487,000
Accrued interest payable, fair value	407,000	487,000
Off-balance sheet instruments
Commitments to extend credit, carrying amount	0	0
Commitments to extend credit, fair value	0	0
Standby letters of credit, carrying amount	0	0
Standby letters of credit, fair value	0	0
With No Stated Maturities [Member] | Fair Value, Inputs, Level 1 [Member]
Financial liabilities
Deposits, fair value	542,740,000	532,404,000
With No Stated Maturities [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities
Deposits, fair value	0	0
With No Stated Maturities [Member] | Fair Value, Inputs, Level 3 [Member]
Financial liabilities
Deposits, fair value	0	0
With No Stated Maturities [Member]
Financial liabilities
Deposits, carrying amount	542,740,000	532,404,000
Deposits, fair value	542,740,000	532,404,000
With Stated Maturities [Member] | Fair Value, Inputs, Level 1 [Member]
Financial liabilities
Deposits, fair value	0	0
With Stated Maturities [Member] | Fair Value, Inputs, Level 2 [Member]
Financial liabilities
Deposits, fair value	256,933,000	273,878,000
With Stated Maturities [Member] | Fair Value, Inputs, Level 3 [Member]
Financial liabilities
Deposits, fair value	0	0
With Stated Maturities [Member]
Financial liabilities
Deposits, carrying amount	253,173,000	269,234,000
Deposits, fair value	256,933,000	273,878,000
Fair Value, Inputs, Level 1 [Member]
Financial assets
Cash and cash equivalents, fair value	15,897,000	15,453,000
Investment securities available-for-sale	4,470,000	4,055,000
Investment securities held-to-maturity, fair value	0	0
Restricted investment in bank stocks, fair value	1,837,000	2,244,000
Loans held-for-sale, fair value	0	0
Net loans, fair value	0	0
Mortgage servicing rights, fair value	0	0
Accrued interest receivable, fair value	0	0
Financial liabilities
Short-term borrowings, fair value	32,851,000	32,488,000
Long-term debt, fair value	0	0
Accrued interest payable, fair value	0	0
Off-balance sheet instruments
Commitments to extend credit, fair value	0	0
Standby letters of credit, fair value	0	0
Fair Value, Inputs, Level 2 [Member]
Financial assets
Cash and cash equivalents, fair value	0	0
Investment securities available-for-sale	373,803,000	395,485,000
Investment securities held-to-maturity, fair value	163,000	166,000
Restricted investment in bank stocks, fair value	0	0
Loans held-for-sale, fair value	1,328,000	1,674,000
Net loans, fair value	0	0
Mortgage servicing rights, fair value	0	0
Accrued interest receivable, fair value	2,981,000	2,803,000
Financial liabilities
Short-term borrowings, fair value	0	0
Long-term debt, fair value	5,412,000	5,694,000
Accrued interest payable, fair value	407,000	487,000
Off-balance sheet instruments
Commitments to extend credit, fair value	0	0
Standby letters of credit, fair value	0	0
Fair Value, Inputs, Level 3 [Member]
Financial assets
Cash and cash equivalents, fair value	0	0
Investment securities available-for-sale	2,091,000	1,962,000
Investment securities held-to-maturity, fair value	0	0
Restricted investment in bank stocks, fair value	0	0
Loans held-for-sale, fair value	0	0
Net loans, fair value	481,469,000	474,330,000
Mortgage servicing rights, fair value	576,000	464,000
Accrued interest receivable, fair value	0	0
Financial liabilities
Short-term borrowings, fair value	0	0
Long-term debt, fair value	0	0
Accrued interest payable, fair value	0	0
Off-balance sheet instruments
Commitments to extend credit, fair value	0	0
Standby letters of credit, fair value	$ 0	$ 0