Note 18 - Retirement Plans - Benefit Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
United States Pension Plan of US Entity [Member]
Benefit obligation, beginning of year	$ 58,556	$ 64,825
Service cost
Interest cost	2,390	2,430	3,310
Actuarial loss/(gain)	427	(5,263)
Benefits paid	(3,655)	(3,436)
Benefit obligation, end of year	57,718	58,556	64,825
Supplemental Employee Retirement Plan [Member]
Benefit obligation, beginning of year	1,800	2,389
Service cost
Interest cost	18	24	33
Actuarial loss/(gain)		(4)
Benefits paid	(609)	(609)
Benefit obligation, end of year	1,209	1,800	2,389
Foreign Pension Plan [Member]
Benefit obligation, beginning of year	22,748	26,700
Service cost	742	778	674
Interest cost	740	589	884
Actuarial loss/(gain)	3,255	(2,397)
Benefits paid	(700)	(697)
Currency translation effect	(1,783)	(2,225)
Benefit obligation, end of year	$ 25,002	$ 22,748	$ 26,700