Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provisional tax expense recognized					$ 35.9
Adjustment to estimate related to executive compensation, tax benefit			$ 2.8
Tax expense for current impact of GILTI provisions			$ 5.0
Effective tax rate, percentage	12.00%	(193.00%)	(11.00%)	49.00%
Earnings (losses) of foreign entities	$ 27.3	$ 15.2	$ 32.7	$ 40.6
Unrecognized tax benefit for uncertain tax positions	27.8		27.8		27.2
Accrued interest and penalties related to income tax liabilities	1.1		1.1		$ 1.2
Decrease in unrecognized tax benefits due to expiration of statutes of limitations and settlement of various audits	3.7		$ 3.7
Tax Cuts and Jobs Act of 2017, foreign tax charge related to remittance of earnings	$ 0.5

Income tax expense (benefit) recognized for Global Intangible Low-Taxed Income.

No definition available.

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- Definition

Tax Cuts and Jobs Act of 2017, incomplete accounting, change in tax rate, deferred tax liability, provisional income tax benefit.

+ References

No definition available.

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- Definition

Tax Cuts and Jobs Act of 2017, incomplete accounting, change in tax rate, provisional income tax expense (benefit).

+ References

No definition available.

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- Definition

Tax Cuts and Jobs Act of 2017, incomplete accounting, transition tax for accumulated foreign earnings, provisional income tax expense.

+ References

No definition available.

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- Definition

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

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-Publisher FASB
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- Definition

The portion of earnings or loss from continuing operations before income taxes that is attributable to foreign operations, which is defined as Income or Loss generated from operations located outside the entity's country of domicile.

+ References

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- Definition

The amount of the unrecognized tax benefit of a position taken for which it is reasonably possible that the total amount thereof will significantly increase or decrease within twelve months of the balance sheet date.

+ References

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

Amount of unrecognized tax benefits.

+ References

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- Definition

Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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