Note 18 - Retirement Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of net periodic benefit cost
Loss on voluntary pension settlement			$ 7,170
United States Pension Plan of US Entity [Member]
Components of net periodic benefit cost
Service cost
Interest cost	2,390	2,430	3,310
Expected return on plan assets	(2,649)	(2,870)	(4,153)
Amortization of prior service cost/(benefit)
Recognized actuarial loss	776	811	522
Loss on voluntary pension settlement			7,170
Net periodic benefit cost	517	371	6,849
Supplemental Employee Retirement Plan [Member]
Components of net periodic benefit cost
Service cost
Interest cost	18	24	33
Expected return on plan assets
Amortization of prior service cost/(benefit)	57	57	57
Recognized actuarial loss	182	154	131
Loss on voluntary pension settlement
Net periodic benefit cost	257	235	221
Foreign Pension Plan [Member]
Components of net periodic benefit cost
Service cost	742	778	674
Interest cost	740	589	884
Expected return on plan assets
Amortization of prior service cost/(benefit)	(5)	(5)	(7)
Recognized actuarial loss	194	330	149
Loss on voluntary pension settlement
Net periodic benefit cost	$ 1,671	$ 1,692	$ 1,700