Note 4 - Securities in a Continuous Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
US Treasury and Government [Member]
Securities in a continuous loss position, less than 12 months, fair value	$ 31,408	$ 46,805
Securities in a continuous loss position, less than 12 months, unrealized losses	$ 18	$ 117
Securities in a continuous loss position, greater than 12 months, fair value
Securities in a continuous loss position, greater than 12 months, unrealized losses
Securities in a continuous loss position, fair value	$ 31,408	$ 46,805
Securities in a continuous loss position, unrealized losses	18	117
US States and Political Subdivisions Debt Securities [Member]
Securities in a continuous loss position, less than 12 months, fair value	3,269	4,741
Securities in a continuous loss position, less than 12 months, unrealized losses	28	32
Securities in a continuous loss position, greater than 12 months, fair value	2,390	2,707
Securities in a continuous loss position, greater than 12 months, unrealized losses	22	28
Securities in a continuous loss position, fair value	5,659	7,448
Securities in a continuous loss position, unrealized losses	50	60
Collateralized Mortgage Backed Securities [Member]
Securities in a continuous loss position, less than 12 months, fair value	11,355	57,561
Securities in a continuous loss position, less than 12 months, unrealized losses	32	$ 567
Securities in a continuous loss position, greater than 12 months, fair value	1,066
Securities in a continuous loss position, greater than 12 months, unrealized losses	6
Securities in a continuous loss position, fair value	12,421	$ 57,561
Securities in a continuous loss position, unrealized losses	38	567
Securities in a continuous loss position, less than 12 months, fair value	46,032	109,107
Securities in a continuous loss position, less than 12 months, unrealized losses	78	716
Securities in a continuous loss position, greater than 12 months, fair value	3,456	2,707
Securities in a continuous loss position, greater than 12 months, unrealized losses	28	28
Securities in a continuous loss position, fair value	49,488	111,814
Securities in a continuous loss position, unrealized losses	$ 106	$ 744