Note 18 - Income Taxes - Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Balance at beginning of year	$ 4,609	$ 7,781	$ 4,477
Additions based on tax positions taken in prior years	5	675	(1)
Additions based on tax positions taken in the current year	2,580	1,532	4,619
Reduction based on tax positions taken in prior years	(837)	(5,379)	(1,314)
Balance at end of year	$ 6,357	$ 4,609	$ 7,781