Acquisition - Schedule of Preliminary Purchase Price Allocation (Detail) - USD ($) $ in Millions		9 Months Ended
	Oct. 01, 2018	Sep. 30, 2019	Dec. 31, 2018
Consideration transferred:
A&S acquisition purchase price adjustment		$ 13.5
Recognized identifiable assets acquired and liabilities assumed:
Goodwill		1,658.7	$ 1,662.3
A&S Business [Member]
Consideration transferred:
Total cash consideration		1,003.4
Total equity consideration		1,458.7
A&S acquisition purchase price adjustment		13.5
Fair value of consideration transferred		2,475.6
Recognized identifiable assets acquired and liabilities assumed:
Less: cash on A&S balance sheet at 10/1/2018		53.6
Receivables		128.9
Inventory		87.0
Prepaids and other current assets		6.7
Property, plant and equipment		176.5
Intangibles	$ 1,454.0	1,454.0
Other non-current assets		7.5
Accounts payable		(98.1)
Accrued payroll		(14.7)
Accrued expenses and other current liabilities		(33.6)
Pension liability and other post employment benefits		(12.0)
Deferred tax liability		(367.4)
Other long term liability		(2.9)
Senior unsecured notes assumed		(400.0)
Total identifiable net assets assumed		985.5
Goodwill		1,490.1
A&S Business [Member] | At Acquisition Date [Member]
Consideration transferred:
Total cash consideration	1,003.4
Total equity consideration	1,458.7
Fair value of consideration transferred	2,462.1
Recognized identifiable assets acquired and liabilities assumed:
Less: cash on A&S balance sheet at 10/1/2018	54.1
Receivables	129.7
Inventory	89.1
Prepaids and other current assets	6.9
Property, plant and equipment	178.3
Intangibles	1,454.0
Other non-current assets	7.9
Accounts payable	(98.9)
Accrued payroll	(15.2)
Accrued expenses and other current liabilities	(33.7)
Pension liability and other post employment benefits	(12.0)
Deferred tax liability	(355.7)
Other long term liability	(2.6)
Senior unsecured notes assumed	(400.0)
Total identifiable net assets assumed	1,001.9
Goodwill	$ 1,460.2
A&S Business [Member] | Measurement Period Adjustments [Member]
Consideration transferred:
A&S acquisition purchase price adjustment		13.5
Fair value of consideration transferred		13.5
Recognized identifiable assets acquired and liabilities assumed:
Less: cash on A&S balance sheet at 10/1/2018		(0.5)
Receivables		(0.8)
Inventory		(2.1)
Prepaids and other current assets		(0.2)
Property, plant and equipment		(1.8)
Other non-current assets		(0.4)
Accounts payable		0.8
Accrued payroll		0.5
Accrued expenses and other current liabilities		0.1
Deferred tax liability		(11.7)
Other long term liability		(0.3)
Total identifiable net assets assumed		(16.4)
Goodwill		$ 29.9