Employee Pension Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Summary of net periodic benefit cost
Interest cost	$ 1,053	$ 1,008	$ 3,159	$ 3,030
Expected return on plan assets	(1,203)	(1,256)	(3,609)	(3,768)
Amortization (adjustment) of net loss	427	(1,417)	1,281	1,503
Other	150		450
Net periodic benefit cost	$ 427	$ (1,665)	1,281	765
Company contribution			1,300	$ 2,300
Expected contributions remainder of current fiscal year			$ 500