Significant Accounting Policies - Summary of Liabilities Related to Integration Plans (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($)
Schedule Of Business Acquisitions Liabilities Related To Integration Plans [Line Items]
Balance at December 31, 2016	$ 73.2
Additions	6.6
Cash payments	(30.6)
Foreign currency exchange rate changes	1.2
Balance at June 30, 2017	50.4
Employee Termination Benefits [Member]
Schedule Of Business Acquisitions Liabilities Related To Integration Plans [Line Items]
Balance at December 31, 2016	38.1
Additions	6.6
Cash payments	(26.9)
Foreign currency exchange rate changes	0.9
Balance at June 30, 2017	18.7
Contract Terminations [Member]
Schedule Of Business Acquisitions Liabilities Related To Integration Plans [Line Items]
Balance at December 31, 2016	35.1
Cash payments	(3.7)
Foreign currency exchange rate changes	0.3
Balance at June 30, 2017	$ 31.7