Note 13 - Condensed Financial Statements of Parent Company (Details) - Condensed Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income
Interest on securities – taxable	$ 6,776	$ 6,798	$ 6,585
Interest on securities – nontaxable	5,438	5,826	6,388
Realized securities losses, net	33	2	(46)
Other income	1,295	1,037	1,342
Expenses
Income before income tax benefit and equity in undistributed net income of subsidiaries	20,573	22,092	23,107
Applicable income tax benefit	(4,740)	(5,178)	(5,317)
Net income	15,833	16,914	17,790
Parent Company [Member]
Income
Dividends from subsidiaries	7,930	7,853	7,882
Interest on securities – taxable	3	2	2
Interest on securities – nontaxable	0	1	19
Realized securities losses, net	0	0	(94)
Other income	1,208	1,250	1,219
	9,141	9,106	9,028
Expenses
Other expenses	2,051	2,046	1,943
Income before income tax benefit and equity in undistributed net income of subsidiaries	7,090	7,060	7,085
Applicable income tax benefit	210	136	160
Income before equity in undistributed net income of subsidiaries	7,300	7,196	7,245
Equity in undistributed net income of subsidiaries	8,533	9,718	10,545
Net income	$ 15,833	$ 16,914	$ 17,790