Note 2 - Investment Securities - Investment Securities by Contractual Maturity (Details) $ in Thousands	Dec. 31, 2016 USD ($)
Securities available for sale, less than one year, amortized cost	$ 8,789
Securities available for sale, one to five years, amortized cost	103,712
Securities available for sale, five to ten years, amortized cost	61,056
Securities available for sale, over ten years, amortized cost	16,812
Securities available for sale, less than one year, fair value	8,803
Securities available for sale, one to five years, fair value	104,873
Securities available for sale, five to ten years, fair value	61,167
Securities available for sale, over ten years, fair value	17,763
Securities held to maturity, less than one year, amortized cost	510
Securities held to maturity, one to five years, amortized cost	0
Securities held to maturity, five to ten years, amortized cost	0
Securities held to maturity, over ten years, amortized cost	0
Securities held to maturity, less than one year, fair value	511
Securities held to maturity, one to five years, fair value	0
Securities held to maturity, five to ten years, fair value	0
Securities held to maturity, over ten years, fair value	0
US Government Agencies Debt Securities [Member]
Securities available for sale, less than one year, amortized cost	0
Securities available for sale, one to five years, amortized cost	7,315
Securities available for sale, five to ten years, amortized cost	9,482
Securities available for sale, over ten years, amortized cost	0
Securities available for sale, less than one year, fair value	0
Securities available for sale, one to five years, fair value	7,292
Securities available for sale, five to ten years, fair value	9,703
Securities available for sale, over ten years, fair value	0
Securities held to maturity, less than one year, amortized cost	510
Securities held to maturity, one to five years, amortized cost	0
Securities held to maturity, five to ten years, amortized cost	0
Securities held to maturity, over ten years, amortized cost	0
Securities held to maturity, less than one year, fair value	511
Securities held to maturity, one to five years, fair value	0
Securities held to maturity, five to ten years, fair value	0
Securities held to maturity, over ten years, fair value	0
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, less than one year, amortized cost	0
Securities available for sale, one to five years, amortized cost	69,188
Securities available for sale, five to ten years, amortized cost	7,124
Securities available for sale, over ten years, amortized cost	16,812
Securities available for sale, less than one year, fair value	0
Securities available for sale, one to five years, fair value	70,071
Securities available for sale, five to ten years, fair value	7,282
Securities available for sale, over ten years, fair value	17,763
US States and Political Subdivisions Debt Securities [Member]
Securities available for sale, less than one year, amortized cost	3,757
Securities available for sale, one to five years, amortized cost	15,758
Securities available for sale, five to ten years, amortized cost	33,950
Securities available for sale, over ten years, amortized cost	0
Securities available for sale, less than one year, fair value	3,775
Securities available for sale, one to five years, fair value	16,050
Securities available for sale, five to ten years, fair value	33,857
Securities available for sale, over ten years, fair value	0
Corporate Debt Securities [Member]
Securities available for sale, less than one year, amortized cost	5,032
Securities available for sale, one to five years, amortized cost	11,451
Securities available for sale, five to ten years, amortized cost	10,500
Securities available for sale, over ten years, amortized cost	0
Securities available for sale, less than one year, fair value	5,028
Securities available for sale, one to five years, fair value	11,460
Securities available for sale, five to ten years, fair value	10,325
Securities available for sale, over ten years, fair value	$ 0