Pension and Other Postretirement Benefits (Details 2) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning balance	$ 498,110	$ 493,952
Service cost	5,961	6,055	$ 5,395
Interest cost	17,383	18,819	19,494
Amendments	826	1,260
Actuarial (gain) loss	(24,449)	23,953
Benefits paid	(31,614)	(29,149)
Transfers in	3,462	2,743
Curtailment gain	0	(7,030)
Plan Settlement	0	(21,074)
Participant contributions	1,120	1,355
Foreign exchange rate changes	(3,158)	7,226
Benefit obligation, ending balance	467,641	498,110	493,952
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning balance	454,438	416,912
Actual return on plan assets	(32,609)	62,281
Company contributions	4,732	14,923
Participant contributions	1,120	1,355
Benefits paid	(31,614)	(29,149)
Plan Settlements	0	(20,857)
Transfers in	3,462	2,743
Foreign exchange rate changes	(3,307)	6,230
Fair value of plan assets, ending balance	396,222	454,438	416,912
Funded/(underfunded) status, December 31	(71,419)	(43,672)
Pension Plan [Member] \| Domestic Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning balance	415,369	389,613
Service cost	4,290	3,931
Interest cost	15,875	17,151
Amendments	0	1,233
Actuarial (gain) loss	(22,193)	28,350
Benefits paid	(25,007)	(24,909)
Transfers in	0	0
Curtailment gain	0	0
Plan Settlement	0	0
Participant contributions	0	0
Foreign exchange rate changes	0	0
Benefit obligation, ending balance	388,334	415,369	389,613
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning balance	375,378	331,260
Actual return on plan assets	(30,681)	56,131
Company contributions	2,925	12,896
Participant contributions	0	0
Benefits paid	(25,007)	(24,909)
Plan Settlements	0	0
Transfers in	0	0
Foreign exchange rate changes	0	0
Fair value of plan assets, ending balance	322,615	375,378	331,260
Funded/(underfunded) status, December 31	(65,719)	(39,991)
Pension Plan [Member] \| Foreign Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning balance	82,741	104,339
Service cost	1,671	2,124
Interest cost	1,508	1,668
Amendments	826	27
Actuarial (gain) loss	(2,256)	(4,397)
Benefits paid	(6,607)	(4,240)
Transfers in	3,462	2,743
Curtailment gain	0	(7,030)
Plan Settlement	0	(21,074)
Participant contributions	1,120	1,355
Foreign exchange rate changes	(3,158)	7,226
Benefit obligation, ending balance	79,307	82,741	104,339
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning balance	79,060	85,652
Actual return on plan assets	(1,928)	6,150
Company contributions	1,807	2,027
Participant contributions	1,120	1,355
Benefits paid	(6,607)	(4,240)
Plan Settlements	0	(20,857)
Transfers in	3,462	2,743
Foreign exchange rate changes	(3,307)	6,230
Fair value of plan assets, ending balance	73,607	79,060	85,652
Funded/(underfunded) status, December 31	(5,700)	(3,681)
Other postretirement benefit plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning balance	37,570	36,853
Service cost	85	83	122
Interest cost	1,358	1,561	1,766
Actuarial (gain) loss	(3,791)	3,806
Benefits paid	(3,435)	(7,251)
Participant contributions	1,280	2,209
Foreign exchange rate changes	9	309
Benefit obligation, ending balance	33,076	37,570	36,853
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning balance	0	0
Company contributions	2,155	5,042
Participant contributions	1,280	2,209
Benefits paid	(3,435)	(7,251)
Fair value of plan assets, ending balance	0	0	$ 0
Funded/(underfunded) status, December 31	$ 33,076	$ 37,570

Defined Benefit Plan, Transfers In, Benefit Obligation

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Defined Benefit Plan, Transfers In, Plan Assets

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Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

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Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 60
-Section 50
-Paragraph 4
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Amount of contributions received by defined benefit plan from participant which increase benefit obligation.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of (increase) decrease in benefit obligation of defined benefit plan from event reducing expected years of future service of present employees or eliminating accrual of benefits for some or all future services of present employees.

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Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

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Amount of foreign currency translation gain (loss) which (increases) decreases benefit obligation of defined benefit plan.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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Amount of cost recognized for passage of time related to defined benefit plan.

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Amount of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan.

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Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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Amount of (increase) decrease to benefit obligation of defined benefit plan from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Includes, but is not limited to, lump-sum cash payment to participant in exchange for right to receive specified benefits, purchase of nonparticipating annuity contract and change from remeasurement.

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Amount of payment, which decreases plan assets of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract.

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