Note 13 - Employee Benefit Plans - Restricted Stock (Details) - Restricted Stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Balance of shares non-vested (in shares)	60,955	43,477	30,503
Balance of shares non-vested, weighted average grant-date price (in dollars per share)	$ 13.62	$ 12.75	$ 10.26
Granted (in shares)	13,386	24,679	28,951
Granted, weighted average grant-date price (in dollars per share)	$ 20.33	$ 15.01	$ 14.78
Vested (in shares)	(28,791)	(7,201)	(15,083)
Vested, weighted average grant-date price (in dollars per share)	$ 12.29	$ 13.13	$ 11.64
Forfeited (in shares)			(894)
Forfeited, weighted average grant-date price (in dollars per share)			$ 12.26
Balance of shares non-vested (in shares)	45,550	60,955	43,477
Balance of shares non-vested, weighted average grant-date price (in dollars per share)	$ 16.44	$ 13.62	$ 12.75