Retirement Plans (Details 13) $ in Thousands	Dec. 31, 2017 USD ($)
Estimated Future Benefit Payments [Abstract]
Expected future benefit payments, year 1	$ 11,781
Expected future benefit payments, year 2	11,677
Expected future benefit payments, year 3	12,347
Expected future benefit payments, year 4	12,866
Expected future benefit payments, year 5	13,712
Expected future benefit payments, year 6-10	77,006
U. S. Pension Plans And U. S. Retiree Healthcare Plan [Member]
Estimated Future Benefit Payments [Abstract]
Expected future benefit payments, year 1	9,385
Expected future benefit payments, year 2	10,114
Expected future benefit payments, year 3	10,287
Expected future benefit payments, year 4	10,777
Expected future benefit payments, year 5	10,749
Expected future benefit payments, year 6-10	58,789
Non-U.S. Pension Plans
Estimated Future Benefit Payments [Abstract]
Expected future benefit payments, year 1	2,396
Expected future benefit payments, year 2	1,563
Expected future benefit payments, year 3	2,060
Expected future benefit payments, year 4	2,089
Expected future benefit payments, year 5	2,963
Expected future benefit payments, year 6-10	$ 18,217

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Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

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Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

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