Revenue Recognition - Summary of Opening and Closing Balances of Contract Liability and Receivables (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
Disaggregation Of Revenue [Line Items]
Accounts Receivable, Beginning Balance	$ 259.8
Accounts Receivable, Closing Balance	269.6
ASU 2014-09 [Member]
Disaggregation Of Revenue [Line Items]
Deferred Revenue (Current), Beginning Balance	7.4
Deferred Revenue (Current), Closing Balance	8.1
Deferred Revenue (Current), Increase/(Decrease)	0.7
Accounts Receivable, Beginning Balance	259.8
Accounts Receivable, Closing Balance	269.6
Accounts Receivable, Increase/(Decrease)	$ 9.8