Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits	$ 0.5	$ 0.5
Accrued unrecognized tax benefits interest and penalties	0.3	$ 0.3
Income tax expense (benefit), attributable to tax cuts and jobs act	(2.1)
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Measurement period adjustment, income tax expense (benefit)	(1.3)
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Measurement period adjustment, income tax expense (benefit)	$ (0.8)