Note 8 - Components of Net Periodic Benefit Cost for Pension Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Components of net periodic pension cost:
Service cost	$ 3,130	$ 5,162	$ 5,165
Interest cost	4,159	4,106	3,553
Expected return on plan assets	(4,782)	(4,200)	(3,400)
Recognized net actuarial loss	1,580	969	3,131
Net periodic pension cost	$ 4,087	$ 6,037	$ 8,449