Note 9 - Retirement Plans (Details) - Components of Net Periodic Benefit Cost for Pension Plans (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Components of net periodic pension cost:
Service cost	$ 5,165	$ 4,452	$ 3,447
Interest cost	3,553	3,315	2,943
Expected return on plan assets	(3,400)	(2,609)	(2,351)
Recognized net actuarial loss	3,131	2,527	958
Net periodic pension cost	$ 8,449	$ 7,685	$ 4,997