Revenue Recognition - Summary of Opening and Closing Balances of Contract Liability and Accounts Receivable (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation Of Revenue [Line Items]
Accounts Receivable, Beginning Balance	$ 243.2
Accounts Receivable, Closing Balance	242.9
ASU 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Deferred Revenue (Current), Beginning Balance	8.4	$ 7.4
Deferred Revenue (Current), Closing Balance	11.1	7.8
Deferred Revenue (Current), Increase/(Decrease)	2.7	0.4
Accounts Receivable, Beginning Balance	243.2	259.8
Accounts Receivable, Closing Balance	242.9	281.8
Accounts Receivable, Increase/(Decrease)	$ (0.3)	$ 22.0