Retirement Plans - Schedule of Weighted Average Assets Allocation and Weighted Average Target Allocation (Details) - United Kingdom Subsidiary - UK Plan	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	100.00%
Asset Allocation	100.00%	100.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	15.00%
Asset Allocation	13.40%	14.10%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	65.00%
Asset Allocation	71.20%	77.30%
Cash
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	10.00%
Asset Allocation	6.10%	8.60%
Real estate
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocation	10.00%
Asset Allocation	9.30%	0.00%

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- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=112275985&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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