Employee Benefit Plans - Assumptions (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Average wage increase	4.50%
Ultimate medical trend rate	5.00%
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Annual rate of increase in the per capita cost of covered benefits	7.00%
Year that rate reaches ultimate trend rate	2027
Effect of one-percentage point change in assumed health care cost trend rates [Abstract]
Effect of one percentage point increase on accumulated postretirement benefit obligation	$ 75
Effect of one percentage point decrease on accumulated postretirement benefit obligation		$ (68)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.15%	3.50%
Ultimate medical trend rate	5.00%	2.33%
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.50%	6.49%	4.00%
Nonqualified Plan [Member] \| Supplemental Employee Retirement Plans, Defined Benefit [Member]
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.30%	3.57%
Average wage increase	4.50%	4.50%
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.57%	3.97%	4.18%
Average wage increase	4.50%	4.50%	4.50%
Domestic Plan [Member] \| Qualified Plan [Member] \| Pension Plan [Member]
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	4.35%	3.65%
Average wage increase		4.00%
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate		4.10%	4.40%
Average wage increase	4.00%	4.00%	4.00%
Expected return on plan assets		7.25%	7.25%
Domestic Plan [Member] \| Qualified Plan [Member] \| Pension Plan [Member] \| Minimum [Member]
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.20%
Expected return on plan assets	6.80%
Domestic Plan [Member] \| Qualified Plan [Member] \| Pension Plan [Member] \| Maximum [Member]
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.65%
Expected return on plan assets	7.25%
Foreign Plan [Member] \| Qualified Plan [Member] \| Pension Plan [Member]
Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	1.83%	1.94%
Average wage increase	2.10%	2.33%
Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	1.94%	2.06%	2.32%
Average wage increase	2.33%	2.34%	2.25%
Expected return on plan assets	4.66%	4.73%	4.95%

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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- Definition

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.

+ References

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-Publisher FASB
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- Definition

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

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

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

+ References

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- Definition

Amount of decrease in accumulated postretirement benefit obligation from one-percentage-point decrease in assumed health care cost trend rate.

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Amount of increase in accumulated postretirement benefit obligation from one-percentage-point increase in assumed health care cost trend rate.

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- Definition

Assumed rate, for next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status.

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- Definition

Ultimate trend rate for health care cost for defined benefit postretirement plan.

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- Definition

Year ultimate health care cost trend rate is expected to be reached, in CCYY format.

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