Note 11 - Reconciliation of the Tax Provision (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	Dec. 31, 2014
Reconciliation Of The Tax Provision [Abstract]
Provision at statutory rate									$ 4,073	$ 3,673	$ 3,958
Tax-exempt interest and dividend income									(1,033)	(1,126)	(1,212)
Bank-owned life insurance									(105)	(104)	(106)
Life insurance proceeds									0	0	(54)
Stock-based compensation expense									30	29	28
State income tax									41	34	0
Other									48	64	30
Net provision	$ 743	$ 821	$ 702	$ 788	$ 571	$ 715	$ 583	$ 701	$ 3,054	$ 2,570	$ 2,644
Provision at statutory rate									34.00%	34.00%	34.00%
Tax-exempt interest and dividend income									(8.60%)	(10.40%)	(10.40%)
Bank-owned life insurance									(0.90%)	(1.00%)	(0.90%)
Life insurance proceeds									(0.00%)	(0.00%)	(0.50%)
Stock-based compensation expense									0.30%	0.30%	0.20%
State income tax									0.30%	0.30%	0.00%
Other									0.40%	0.60%	0.30%
Total									25.50%	23.80%	22.70%