Note 4 - Securities - Expected Maturities of Investment Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale securities, amortized cost, one year or less	$ 4,636
Available-for-sale securities, fair value, one year or less	4,641
Held-to-maturity securities, amortized cost, One year or less
Held-to-maturity securities, fair value, one year or less
Available-for-sale securities, amortized cost, one year through five years	69,694
Available-for-sale securities, fair value, one year through five years	68,698
Held-to-maturity securities, amortized cost, one year through five years	4,604
Held-to-maturity securities, fair value, one year through five years	4,723
Available-for-sale securities, amortized cost, five years through ten years	43,350
Available-for-sale securities, fair value, five years through ten years	43,287
Held-to-maturity securities, amortized cost, five years through ten years	13,469
Held-to-maturity securities, fair value, five years through ten years	13,572
Available-for-sale securities, amortized cost, after ten years	58,838
Available-for-sale securities, fair value, after ten years	58,548
Held-to-maturity securities, amortized cost, after ten years	13,114
Held-to-maturity securities, fair value, after ten years	13,079
Available-for-sale securities, amortized cost, total	176,518
Available-for-sale securities, fair value, total	175,174	$ 159,030
Held-to-maturity securities, amortized cost, total	31,187	$ 35,899
Held-to-maturity securities, fair value, total	$ 31,374