Revenues and Gross Profit - Domestic and Foreign Total Revenues (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Consolidated total revenues	$ 4,729.9	$ 4,739.1	$ 4,244.3
Domestic
Segment Reporting Information [Line Items]
Consolidated total revenues	4,674.4	4,676.3	4,166.4
Foreign
Segment Reporting Information [Line Items]
Consolidated total revenues	$ 55.5	$ 62.8	$ 77.9