Pensions and Other Postretirement Benefit Plans (Schedule of Plan Benefit Obligations) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension plans
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	$ 227,211	$ 201,450
Service cost	2,279	2,543	$ 2,723
Interest cost	6,172	7,216
Plan participants' contributions	198	243
Actuarial (gain)/loss	13,309	22,645
Benefits paid	(8,123)	(8,404)
Settlements and curtailments	(474)	(1,768)
Plan amendments and other	(204)	152
Foreign currency changes	5,432	3,134
Benefit obligation, end of year	245,800	227,211	201,450
Accumulated benefit obligation	$ 236,321	$ 218,006
Pension plans \| United States
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	2.65%	3.40%
Compensation increase	0.00%	0.00%
Pension plans \| Foreign Plan
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	1.91%	2.31%
Compensation increase	2.71%	2.81%
Pension plans \| Switzerland
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, end of year	$ 6,000
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Cash balance interest crediting rate	50.00%	0.25%
Other postretirement benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	$ 54,384	$ 51,127
Service cost	200	189	232
Interest cost	1,712	2,115
Plan participants' contributions	0	0
Actuarial (gain)/loss	(4,794)	4,686
Benefits paid	(3,555)	(3,782)
Settlements and curtailments	0	0
Plan amendments and other	0	0
Foreign currency changes	30	49
Benefit obligation, end of year	47,977	54,384	$ 51,127
Accumulated benefit obligation	$ 0	$ 0
Other postretirement benefits \| United States
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	2.38%	3.27%
Compensation increase		3.00%
Other postretirement benefits \| Foreign Plan
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	2.75%	3.05%
Compensation increase	2.75%	3.00%
Other postretirement benefits \| Switzerland
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Cash balance interest crediting rate	0.00%	0.00%

Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

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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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Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

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Weighted-average interest crediting rate used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, cash balance and other defined benefit plans with promised interest crediting rate.

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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.

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Amount of contributions received by defined benefit plan from participant which increase benefit obligation.

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- Definition

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

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- Definition

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

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- Definition

Amount of increase (decrease) in benefit obligation of defined benefit plan from change, classified as other.

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

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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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