Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of January 1,	$ 13.2	$ 24.4
Gross increases for tax positions of prior years	0.4	0.8
Gross increases for tax positions of current year	2.7	2.7
Decreases due to settlements and other prior year tax positions	(1.7)	(4.2)
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	2.2	10.5
Balance as of December 31,	12.4	13.2
Reserves related to potential interest and penalties as of December 31,	0.9	1.2
Unrecognized tax benefits as of December 31,	$ 13.3	$ 14.4