Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans (Details) - Loans Past Due 90 Days or More and Impaired Loans - USD ($) $ in Thousands		3 Months Ended			6 Months Ended				12 Months Ended
		Jun. 30, 2015		Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014		Dec. 31, 2014
Loans Past Due 90 Days or More and Impaired Loans [Abstract]
Loans past due 90 days or more and still accruing		$ 80	[1]	$ 266	$ 80	[1]	$ 266		$ 207	[1]
Ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees		0.01%		0.04%	0.01%		0.04%		0.03%
Accruing restructured loans		$ 5,943		$ 6,240	$ 5,943		$ 6,240		$ 6,040
Impaired loans:
Impaired loans with no valuation allowance		12,182	[2],[3]	8,155	12,182	[2],[3]	8,155		7,615	[2],[3]
Impaired loans with a valuation allowance		2,503	[2],[3]	2,989	2,503	[2],[3]	2,989		7,506	[2],[3]
Total impaired loans		14,685	[2],[3]	11,144	14,685	[2],[3]	11,144		15,121	[2],[3]
Valuation allowance		(151)	[2]	(291)	(151)	[2]	(291)		(282)	[2]
Impaired loans, net of allowance		14,534		10,853	14,534		10,853		14,839
Average recorded investment in impaired loans(1)	[3]	15,543		11,898	15,543	[2]	11,898	[2]	16,311
Interest income recognized on impaired loans, after designation as impaired		$ 172		$ 191	$ 172	[2]	$ 191	[2]	$ 473

[1] Only classes with past-due or nonaccrual loans are shown.

[2] Only classes with impaired loans are shown.

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