Note 12 - Condensed Financial Statements of Parent Company - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities
Net income	$ 17,466	$ 16,151	$ 14,092
Adjustment to reconcile net income to net cash provided by operating activities:
Gain on sale of securities	(566)	(17)	(14)
Other assets	(1,340)	2,899	(2,537)
Net change in other liabilities	2,465	404	101
Net cash provided by operating activities	18,832	19,796	10,993
Cash Flows from Investing Activities
Net change in interest-bearing deposits	(33,390)	7,742	29,035
Net cash used in investing activities	(61,678)	(3,629)	(20,192)
Cash Flows from Financing Activities
Cash dividends paid	(9,032)	(8,419)	(8,141)
Shares repurchased	(18,525)
Net cash provided by (used in) financing activities	40,254	(16,211)	8,151
Net change in cash	(2,592)	(44)	(1,048)
Parent Company [Member]
Cash Flows from Operating Activities
Net income	17,466	16,151	14,092
Adjustment to reconcile net income to net cash provided by operating activities:
Deficit (equity) in undistributed net income of subsidiaries	(10,349)	7,658	6,532
Gain on sale of securities			(4)
Net change in refundable income taxes due from subsidiaries	(27)	(228)	(146)
Other assets	(173)	(109)	(156)
Net change in other liabilities	221	115	(40)
Net cash provided by operating activities	27,836	8,271	7,214
Cash Flows from Investing Activities
Net change in interest-bearing deposits	(266)	146	807
Maturities, sales and calls of securities available for sale			192
Capital distribution to subsidiary			(100)
Net cash used in investing activities	(266)	146	899
Cash Flows from Financing Activities
Cash dividends paid	(9,032)	(8,419)	(8,141)
Shares repurchased	(18,525)
Net cash provided by (used in) financing activities	(27,557)	(8,419)	(8,141)
Net change in cash	13	(2)	(28)
Cash due from subsidiaries at beginning of year	44	46	74
Cash due from subsidiaries at end of year	$ 57	$ 44	$ 46