Pension and Other Postretirement Benefits (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Contribution expense	$ 6,921	$ 6,644	$ 5,907
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension lump-sum settlement charge	0	21,074
Curtailment gain	$ 0	7,217	$ 0
Retirement Savings Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Annual retirement contribution percent	4.00%
Facility Closing [Member]
Defined Benefit Plan Disclosure [Line Items]
Curtailment gain		$ 7,217
Facility Closing [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Curtailment gain	$ 7,217