Note 13 - Condensed Financial Statements of Parent Company (Details) - Condensed Statements of Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income
Interest on securities – taxable	$ 6,798	$ 6,585	$ 6,460
Interest on securities – nontaxable	5,826	6,388	6,463
Realized securities losses, net	2	(46)	60
Other income	868	997	669
Expenses
Income before income tax benefit and equity in undistributed net income of subsidiaries	22,092	23,107	22,992
Applicable income tax benefit	(5,178)	(5,317)	(5,245)
Net income	16,914	17,790	17,747
Parent Company [Member]
Income
Dividends from subsidiaries	7,853	7,882	7,639
Interest on securities – taxable	2	2	5
Interest on securities – nontaxable	1	19	33
Realized securities losses, net		(94)
Other income	1,250	1,219	1,213
	9,106	9,028	8,890
Expenses
Other expenses	2,046	1,943	1,791
Income before income tax benefit and equity in undistributed net income of subsidiaries	7,060	7,085	7,099
Applicable income tax benefit	136	160	136
Income before equity in undistributed net income of subsidiaries	7,196	7,245	7,235
Equity in undistributed net income of subsidiaries	9,718	10,545	10,512
Net income	$ 16,914	$ 17,790	$ 17,747