Components of Net Periodic Benefit Cost (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net pension cost of plans
Interest cost	$ 1,951	$ 1,931	$ 3,901	$ 3,862
Expected return on plan assets	(2,061)	(2,159)	(4,122)	(4,319)
Recognized actuarial loss	596	1,557	1,193	3,114
Net periodic benefit cost	$ 486	$ 1,329	$ 972	$ 2,657