Revenue from Contracts with Customers - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Receivables related to revenue from contract with customer	$ 543,600,000		$ 543,600,000		$ 516,100,000
Impairments related to revenue receivables	0	$ 0	0	$ 0
Deferred revenue	15,600,000		15,600,000		12,800,000
Deferred revenue recognized	7,300,000	$ 5,100,000	8,800,000	$ 5,600,000
Capitalized costs	$ 1,700,000		$ 1,700,000		$ 0