Note 11 - Retirement Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Domestic Plan [Member]
Components of net periodic (benefit)/cost
Interest cost	$ 510	$ 554
Expected return on plan assets	(792)	(677)
Recognized actuarial loss	179	200
Net periodic (benefit)/cost	(103)	77
Foreign Plan [Member]
Components of net periodic (benefit)/cost
Service cost	270	225
Interest cost	194	175
Recognized actuarial loss	103	86
Amortization of prior service cost/(benefit)	(1)	(1)
Net periodic (benefit)/cost	$ 566	$ 485