Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax Note Textuals [Line Items]
Cash and Cash Equivalents	$ 389.8	$ 460.7	$ 415.7	$ 584.0
Net operating loss carryforwards in Luxembourg	228.1
Excess Tax benefit from stock activity	2.7
Excess tax benefit from equity compensation activity	$ 0.0	3.2	3.4
The tax benefits recognized in the Consolidated Financial Statements from such positions are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement	The tax benefits recognized in the Consolidated Financial Statements from such positions are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement.
Estimated change in unrecognized tax benefits	$ 16.0
Interest (income) expense related to tax matters	(2.4)	(2.9)	(5.7)
Interest accrued from income tax examinations	4.1	6.8	9.8
Tax Matters Agreement Receivable, Total			$ 14.8
Tax Matters Agreement, Collection		$ 1.5
Continuing Operations [Member]
Tax Note Textuals [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	24.7
Discontinued Operations [Member]
Tax Note Textuals [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 2.5
Impacts from U.S. Tax Act of 2017 [Member]
Tax Note Textuals [Line Items]
Dividend Received Deduction Percentage	100.00%
Deferred taxes not provided for excess of financial reporting over tax basis of investments in foreign subsidiaries	$ 218.0
Existing Post 1986 Foreign Earnings Subject to One Time US Tax	1,200.0
One Time Provisional US Tax Expense on Post 1986 Foreign Earnings	57.9
Tax Expense on Undistributed Foreign Earnings	37.6
Reversal of Previously Recorded Tax Liability on Undistributed Foreign Earnings	$ 52.3
2018 U.S. Federal Statutory Tax Rate	21.00%
2017 U.S. Federal Statutory Tax Rate	35.00%
Remeasurement of US Net Deferred Taxes	$ 86.0
Uncertain Deferred Tax Assets for Officer Compensation	$ 3.6