Note 9 - Fair Value Disclosure - Assets and Liabilities Reported Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available for sale securities	$ 115,889	$ 106,208
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]
Available for sale securities	58,380	66,156
Fair Value, Inputs, Level 2 [Member] | US States and Political Subdivisions Debt Securities [Member]
Available for sale securities	37,808	35,735
Fair Value, Inputs, Level 2 [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available for sale securities	17,859	2,619
Fair Value, Inputs, Level 1 [Member] | Equity Securities - Mutual Funds [Member]
Available for sale securities	510	507
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Available for sale securities	$ 1,332	$ 1,191