Goodwill and Other Intangible Assets - Components of Other Intangible Assets (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Intangible Assets by Major Class [Line Items]
Total estimated life	16 years
Gross amortized other intangible assets	$ 472.7	$ 472.8
Accumulated Amortization	(137.8)	(120.7)
Net	334.9	352.1
Intangible Assets, Net (Excluding Goodwill)	$ 668.8	686.4
Non-compete agreements
Intangible Assets by Major Class [Line Items]
Total estimated life	4 years
Gross amortized other intangible assets	$ 2.6	2.6
Dealer/customer related
Intangible Assets by Major Class [Line Items]
Total estimated life	17 years
Gross amortized other intangible assets	$ 460.3	460.3
Developed technology
Intangible Assets by Major Class [Line Items]
Total estimated life	5 years
Gross amortized other intangible assets	$ 9.8	9.9
Brand/trade names
Intangible Assets by Major Class [Line Items]
Non-amortizable—brand/trade names	$ 333.9	$ 334.3