Note 5 - Retirement Plans (Details) - Components of Net Periodic Benefit Cost for Pension Plans (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Components of Net Periodic Benefit Cost for Pension Plans [Abstract]
Service cost	$ 1,279	$ 1,291	$ 3,886	$ 3,871
Interest cost	1,099	967	3,336	2,899
Expected return on plan assets	(1,123)	(926)	(3,410)	(2,774)
Loss amortization	263	824	799	2,468
Net periodic benefit cost	$ 1,518	$ 2,156	$ 4,611	$ 6,464