Restructuring - Costs Included in Selling, General & Administrative Expenses (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 6.7	$ 25.0	$ 7.8	$ 30.6
Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	6.4	4.6	7.5	10.0
Other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0.3	$ 20.4	$ 0.3	$ 20.6

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration