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Pension and Post-Employment Benefits - Unfunded Defined Benefit Pension Plan (Detail) - German Plan [Member] - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Plan net pension charge: |  |  |
Interest cost on PBO | $ 0.2 | $ 0.2 | $ 0.2
Amortization of actuarial net loss | 0.4 | 0.4 | 0.2
Plan net pension (credit)/charge | $ 0.6 | $ 0.6 | $ 0.4
Plan assumptions at December 31, (%): |  |  |
Discount rate | 1.90% | 1.70% | 1.80%
Inflation rate | 1.75% | 1.75% | 1.75%
Rate of increase in compensation levels | 2.75% | 2.75% | 2.75%

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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(4) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 Reference 2: 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 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e2709-114920 + Details
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