Note 2 - Investment Securities (Details) - Unrealized Loss Positions of Available-for-sale Securities - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Note 2 - Investment Securities (Details) - Unrealized Loss Positions of Available-for-sale Securities [Line Items]
Securities available-for-sale in a continuous unrealized loss position, less than 12 months, fair value	$ 13,130	$ 7,935
Securities available-for-sale in a continuous unrealized loss position, less than 12 months, unrealized loss	(148)	(74)
Securities available-for-sale in a continuous unrealized loss position, 12 months or more, fair value	8,519	13,322
Securities available-for-sale in a continuous unrealized loss position, 12 months or more, unrealized loss	(148)	(225)
Securities available-for-sale in a continuous unrealized loss position, fair value	21,649	21,257
Securities available-for-sale in a continuous unrealized loss position, unrealized loss	(296)	(299)
US Government Agencies Debt Securities [Member]
Note 2 - Investment Securities (Details) - Unrealized Loss Positions of Available-for-sale Securities [Line Items]
Securities available-for-sale in a continuous unrealized loss position, less than 12 months, fair value	8,878	5,568
Securities available-for-sale in a continuous unrealized loss position, less than 12 months, unrealized loss	(106)	(48)
Securities available-for-sale in a continuous unrealized loss position, 12 months or more, fair value	5,275	7,078
Securities available-for-sale in a continuous unrealized loss position, 12 months or more, unrealized loss	(85)	(132)
Securities available-for-sale in a continuous unrealized loss position, fair value	14,153	12,646
Securities available-for-sale in a continuous unrealized loss position, unrealized loss	(191)	(180)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Note 2 - Investment Securities (Details) - Unrealized Loss Positions of Available-for-sale Securities [Line Items]
Securities available-for-sale in a continuous unrealized loss position, less than 12 months, fair value	3,447	742
Securities available-for-sale in a continuous unrealized loss position, less than 12 months, unrealized loss	(32)	(6)
Securities available-for-sale in a continuous unrealized loss position, 12 months or more, fair value	2,718	4,058
Securities available-for-sale in a continuous unrealized loss position, 12 months or more, unrealized loss	(58)	(58)
Securities available-for-sale in a continuous unrealized loss position, fair value	6,165	4,800
Securities available-for-sale in a continuous unrealized loss position, unrealized loss	(90)	(64)
US States and Political Subdivisions Debt Securities [Member]
Note 2 - Investment Securities (Details) - Unrealized Loss Positions of Available-for-sale Securities [Line Items]
Securities available-for-sale in a continuous unrealized loss position, less than 12 months, fair value	805	1,625
Securities available-for-sale in a continuous unrealized loss position, less than 12 months, unrealized loss	(10)	(20)
Securities available-for-sale in a continuous unrealized loss position, 12 months or more, fair value	526	2,186
Securities available-for-sale in a continuous unrealized loss position, 12 months or more, unrealized loss	(5)	(35)
Securities available-for-sale in a continuous unrealized loss position, fair value	1,331	3,811
Securities available-for-sale in a continuous unrealized loss position, unrealized loss	$ (15)	$ (55)