Note 13 - Income Taxes - Reconciliation of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Provision at federal statutory tax rate									$ 3,196	$ 2,440
State income tax-net of federal tax benefit									111	107
Change in state statutory tax rate									(4)	(4)
Tax-exempt interest income									(416)	(405)
Bank-owned life insurance income									(62)	(83)
Captive insurance net premiums									(294)	(322)
Nondeductible acquisition expense										219
Other									(8)	12
Totals	$ 626	$ 666	$ 667	$ 564	$ 501	$ 507	$ 487	$ 469	$ 2,523	$ 1,964
Effective tax rate									26.80%	27.40%