Internal-Use Software - Additional Information (Detail) - Early Adoption ASU 2018-15 [Member] - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Capitalized implementation costs net of amortizations, for software services	$ 14.2	$ 14.2	$ 10.6
Capitalized implementation costs during the period	$ 0.9	$ 4.5
Minimum [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Capitalized implementation costs amortization period		3 years
Maximum [Member]
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]
Capitalized implementation costs amortization period		10 years