Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans (Details) - Loans Past Due 90 Days or More and Impaired Loans (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Loans Past Due 90 Days or More and Impaired Loans [Abstract]
Loans past due 90 days or more and still accruing	$ 207		$ 190
Ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees	0.03%		0.03%
Accruing restructured loans	6,040		6,191
Impaired loans with no valuation allowance	7,615	[1]	10,635	[1]
Impaired loans with no valuation allowance			10,372
Impaired loans with a valuation allowance	7,506	[1]	2,354	[1]
Impaired loans with a valuation allowance			2,613
Total impaired loans	15,121	[1]	12,989	[1]
Total impaired loans	15,434		12,985
Valuation allowance	(282)		(624)
Impaired loans, net of allowance	14,839		12,361
Average recorded investment in impaired loans(1)	16,311	[1],[2]	16,654	[1]	13,540	[1]
Income recognized on impaired loans, after designation as impaired	473	[2]	267		9
Amount of income recognized on a cash basis	$ 0		$ 0

[1] Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

[2] Only classes with impaired loans are shown.