Segment Information - Schedule of Goodwill and Intangible Assets Net of Accumulated Amortization (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Goodwill	$ 147.3	$ 161.4
Intangible Assets, Net of Accumulated Amortization	60.5	91.8
U.S. Operations
Segment Reporting Information [Line Items]
Goodwill	118.6	123.5
Intangible Assets, Net of Accumulated Amortization	0.0	0.0
International Operations
Segment Reporting Information [Line Items]
Goodwill	28.7	37.9
Intangible Assets, Net of Accumulated Amortization	$ 60.5	$ 91.8