Note 14 - Accumulated Other Comprehensive Loss (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Unrealized Gain (Loss) on Investments	$ (251)	$ (177)	$ (3,333)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, before Tax	200	1,000	3,000
Equity Securities [Member]
Unrealized Gain (Loss) on Investments	$ 2,300	$ 2,600	$ 300