Taxation - Reconciliation of beginning and ending amounts of unrecognized tax benefits (Details) $ in Millions	9 Months Ended
Sep. 30, 2019 USD ($)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at December 31, 2018	$ 20.0
Additions for tax positions related to the current year	1.0
Additions for tax positions related to prior years	0.2
Additions for tax positions related to acquisitions	54.1
Other reductions for tax positions related to prior years	(5.3)
Balance at September 30, 2019	$ 70.0

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
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- Definition

Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

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-Name Accounting Standards Codification
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- Definition

Amount of increase in unrecognized tax benefits resulting from acquisitions.

+ References

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- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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