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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, 2017	Dec. 31, 2016	Dec. 31, 2015
Plan net pension charge:
Service cost	$ 0.2	$ 0.2	$ 0.2
Interest cost on PBO	0.2	0.2	0.2
Amortization of actuarial net loss	0.4	0.2	0.3
Net pension charge	$ 0.8	$ 0.6	$ 0.7
Plan assumptions at December 31, (%):
Discount rate	1.70%	1.80%	2.40%
Inflation rate	1.75%	1.75%	1.75%
Rate of increase in compensation levels	2.75%	2.75%	2.75%

X

- Definition

Defined benefit plan assumptions used calculating net periodic benefit cost inflation rate.

+ References

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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/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)(4)
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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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-Name Accounting Standards Codification
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-Section 50
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- Definition

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

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

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- Definition

Amount of cost recognized for passage of time related to defined benefit plan.

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-Publisher FASB
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- Definition

Amount of net periodic benefit cost (credit) for defined benefit plan.

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-Publisher FASB
-Name Accounting Standards Codification
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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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-Name Accounting Standards Codification
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