Note 10 - Income Taxes - Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax provision computed at statutory rate									$ 2,095	$ 1,689	$ 843
Tax exempt interest									(573)	(582)	(394)
Effect of change in tax rate									7,661
Deferred tax asset valuation allowance adjustment									(12,214)	(1,508)	(937)
Other									112	282	462
Total benefit for income taxes	$ (2,881)	$ 4	$ (8)	$ (34)	$ (50)	$ (32)	$ (12)	$ (25)	$ (2,919)	$ (119)	$ (26)