Note 11 - Warranty Costs - Warranty Costs Accrual (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Warranty accrual	$ 43,932	$ 40,691
Warranty costs accrued during the period	10,699	10,823
Warranty costs paid during the period	(11,986)	(9,941)
Warranty accrual	$ 42,645	$ 41,573