Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Components Of Income Tax Expense Benefit [Line Items]
Income tax effective rate	11.50%	(50.90%)	300.30%	(28.40%)
CARES Act income tax expenses benefit			$ 0.0
Internal Revenue Service [Member]
Components Of Income Tax Expense Benefit [Line Items]
Income tax benefit	$ 0.1		17.8
Minimum [Member]
Components Of Income Tax Expense Benefit [Line Items]
Decrease in unrecognized tax benefits	0.1		0.1
Maximum [Member]
Components Of Income Tax Expense Benefit [Line Items]
Decrease in unrecognized tax benefits	$ 0.6		$ 0.6