Note 7 - Net Periodic Pension Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Service cost	$ 1,077	$ 1,054
Interest cost	1,307	1,206
Expected return on plan assets	(1,325)	(1,345)
Amortization of prior service benefit	(84)	(84)
Amortization of net loss	1,093	1,065
Net periodic benefit cost	$ 2,068	$ 1,896