Share-based Compensation (Narrative) (Details)	3 Months Ended
Mar. 31, 2019 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of annual incentive compensation receivable in shares	100.00%
2019 Challenge Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period	3 years
Award vesting rights	100.00%
Expiration period	10 years
2018 PSUs \| PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period	2 years
2018 PSUs \| PSUs \| April 1, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights	50.00%
2018 PSUs \| PSUs \| October 1, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights	50.00%
2018 PSUs \| PSUs \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance range	50.00%
Award expected performance	50.00%
2018 PSUs \| PSUs \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance range	125.00%
Award expected performance	150.00%
Class A \| 2019 Challenge Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of ordinary share rights for each performance share	1
Class C \| 2019 Challenge Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of ordinary share rights for each performance share	1

Number of Ordinary Shares Rights for Each Performance Share

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Expected Performance

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Performance Period

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Performance Range

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- Definition

Shareholder Inventive Program, Percent of Annual Incentive Compensation

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Percentage of vesting of share-based compensation awards.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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