Retirement Plans - Estimated Future Benefit Payments (Details 14) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 259,752	$ 286,539
Post-Retirement Life Insurance Plan
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0	$ 0
Estimated Future Benefit Payments
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	407
2017	393
2018	379
2019	365
2020	351
2024-2027	1,551
Total	3,446
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	258,327	284,762	292,044
Estimated Future Benefit Payments
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	15,537
2017	15,519
2018	15,409
2019	15,226
2020	14,988
2024-2027	70,462
Total	147,141
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,425	$ 1,777	$ 1,523
Estimated Future Benefit Payments
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	52
2017	57
2018	66
2019	91
2020	82
2024-2027	658
Total	$ 1,006