Commitments, Contingencies and Off-Balance Sheet Arrangements - Contractual Obligations (Detail) $ in Millions	Dec. 31, 2017 USD ($)
Note Purchase Agreements [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2018	$ 100.0
Contractual Obligations, Payments Due by Period, 2019	100.0
Contractual Obligations, Payments Due by Period, 2020	100.0
Contractual Obligations, Payments Due by Period, 2021	75.0
Contractual Obligations, Payments Due by Period, 2022	200.0
Contractual Obligations, Payments Due by Period, Thereafter	2,223.0
Contractual Obligations, Payments Due by Period, Total	2,798.0
Multi Currency Credit Agreement [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2018	190.0
Contractual Obligations, Payments Due by Period, Total	190.0
Premium Financing Debt Facility [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2018	151.1
Contractual Obligations, Payments Due by Period, Total	151.1
Interest On Debt [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2018	120.6
Contractual Obligations, Payments Due by Period, 2019	115.1
Contractual Obligations, Payments Due by Period, 2020	110.7
Contractual Obligations, Payments Due by Period, 2021	105.7
Contractual Obligations, Payments Due by Period, 2022	100.5
Contractual Obligations, Payments Due by Period, Thereafter	368.2
Contractual Obligations, Payments Due by Period, Total	920.8
Total Debt Obligations [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2018	561.7
Contractual Obligations, Payments Due by Period, 2019	215.1
Contractual Obligations, Payments Due by Period, 2020	210.7
Contractual Obligations, Payments Due by Period, 2021	180.7
Contractual Obligations, Payments Due by Period, 2022	300.5
Contractual Obligations, Payments Due by Period, Thereafter	2,591.2
Contractual Obligations, Payments Due by Period, Total	4,059.9
Operating Lease Obligations [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2018	103.2
Contractual Obligations, Payments Due by Period, 2019	88.5
Contractual Obligations, Payments Due by Period, 2020	74.3
Contractual Obligations, Payments Due by Period, 2021	62.5
Contractual Obligations, Payments Due by Period, 2022	47.2
Contractual Obligations, Payments Due by Period, Thereafter	104.5
Contractual Obligations, Payments Due by Period, Total	480.2
Less Sublease Arrangements [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2018	(0.7)
Contractual Obligations, Payments Due by Period, 2019	(0.4)
Contractual Obligations, Payments Due by Period, 2020	(0.4)
Contractual Obligations, Payments Due by Period, 2021	(0.4)
Contractual Obligations, Payments Due by Period, 2022	(0.2)
Contractual Obligations, Payments Due by Period, Total	(2.1)
Outstanding Purchase Obligations [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2018	42.9
Contractual Obligations, Payments Due by Period, 2019	19.5
Contractual Obligations, Payments Due by Period, 2020	8.3
Contractual Obligations, Payments Due by Period, 2021	2.2
Contractual Obligations, Payments Due by Period, 2022	2.0
Contractual Obligations, Payments Due by Period, Total	74.9
Total Contractual Obligations [Member]
Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]
Contractual Obligations, Payments Due by Period, 2018	707.1
Contractual Obligations, Payments Due by Period, 2019	322.7
Contractual Obligations, Payments Due by Period, 2020	292.9
Contractual Obligations, Payments Due by Period, 2021	245.0
Contractual Obligations, Payments Due by Period, 2022	349.5
Contractual Obligations, Payments Due by Period, Thereafter	2,695.7
Contractual Obligations, Payments Due by Period, Total	$ 4,612.9

Commitments Contingencies And Off Balance Sheet Arrangements [Line Items]

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- Definition

Amount of the recorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25383-109308

+ Details

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Amount of the recorded unconditional purchase obligation maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of the recorded unconditional purchase obligation maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of the recorded unconditional purchase obligation maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of the recorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of the recorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of the recorded unconditional purchase obligation maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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