Employee Benefit Plans - Obligations and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in plan assets:
Funded percent	81.00%	84.00%
Pension Plans
Change in benefit obligations:
Benefit obligations at January 1	$ 2,298,902	$ 2,228,762
Service cost	12,108	12,345
Interest cost	78,234	86,431
Actuarial (gain) loss	(120,934)	100,905
Pension annuity settlement	0	(66,423)
Benefits paid	(104,560)	(104,054)
Foreign currency exchange rate changes	(28,607)	40,936
Benefit obligations at December 31	2,135,143	2,298,902	$ 2,228,762
Change in plan assets:
Fair value of plan assets at January 1	1,941,330	1,787,075
Actual return on plan assets	(108,386)	244,916
Employer contribution	27,741	41,219
Benefits paid	(104,560)	(104,054)
Foreign currency exchange rate changes	(30,582)	43,473
Fair value of plan assets at December 31	1,725,543	1,941,330	1,787,075
Funded status	(409,600)	(357,572)
Company Administered Plan [Member] \| Pension Plans
Change in benefit obligations:
Service cost	12,108	12,345	12,977
Interest cost	$ 78,234	$ 86,431	$ 94,476

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.

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Amount of payment, which decreases benefit obligation 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. Excludes decreases to benefit obligation for remeasurement due to settlement.

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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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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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

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Percentage of plan assets to benefit obligation of defined benefit plan.

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No definition available.

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

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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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