Note 17 - Parent Only Condensed Financial Statements - Condensed Statements of Cash Flows (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 15,512,000	$ 13,992,000	$ 8,189,000
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	224,000	199,000	152,000
(Increase) decrease in other assets	(100,000)	(1,397,000)	(513,000)
Net cash provided by operating activities	15,477,000	15,639,000	11,478,000
Cash flows from financing activities:
Cash dividends paid on common stock	(2,373,000)	(1,842,000)	(1,398,000)
Payment on note payable			(2,375,000)
Proceeds from exercise of stock options	144,000	330,000	261,000
Net cash used in financing activities	21,485,000	65,380,000	79,949,000
Increase in cash and cash equivalents	256,000	(40,851,000)	24,891,000
Cash and cash equivalents at beginning of year	46,686,000	87,537,000	62,646,000
Cash and cash equivalents at end of year	46,942,000	46,686,000	87,537,000
Parent Company [Member]
Cash flows from operating activities:
Net income	15,512,000	13,992,000	8,189,000
Adjustments to reconcile net income to net cash provided by operating activities:
Undistributed income of subsidiary	(13,261,000)	(12,479,000)	(4,538,000)
Stock-based compensation expense	54,000	47,000	37,000
(Increase) decrease in other assets	(56,000)	51,000	(76,000)
Decrease (increase) in other liabilities	(17,000)	25,000	2,000
Net cash provided by operating activities	2,232,000	1,636,000	3,614,000
Cash flows from financing activities:
Cash dividends paid on common stock	(2,373,000)	(1,842,000)	(1,398,000)
Payment on note payable			(2,375,000)
Proceeds from exercise of stock options	144,000	330,000	261,000
Net cash used in financing activities	(2,229,000)	(1,512,000)	(3,512,000)
Increase in cash and cash equivalents	3,000	124,000	102,000
Cash and cash equivalents at beginning of year	507,000	383,000	281,000
Cash and cash equivalents at end of year	$ 510,000	$ 507,000	$ 383,000