Components of Net Periodic Benefit Cost (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net pension cost of plans
Interest cost	$ 1,950	$ 1,931	$ 5,851	$ 5,793
Expected return on plan assets	(2,061)	(2,159)	(6,183)	(6,478)
Recognized actuarial loss	596	1,556	1,789	4,671
Net periodic benefit cost	$ 485	$ 1,328	$ 1,457	$ 3,986