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
Income Tax Disclosure [Abstract]
Net operating losses carryback period			2 years
Capital losses carryback period			3 years
Change in valuation allowance	$ 1.2	$ 2.2	$ 1.2	$ 1.6
Unrecognized tax benefits	2.7		2.7
Accrued interest expense	$ 0.5		$ 0.5