Goodwill and Other Identifiable Intangible Assets - Identifiable Intangible Assets (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Acquired Intangible Assets by Major Class [Line Items]
Impairment of Intangible Assets (Excluding Goodwill)	$ 0	$ 0	$ 0
Finite-life intangibles, cost	482,800,000	460,400,000
Accumulated amortization	(337,500,000)	(294,600,000)
Finite-life intangibles, net	145,300,000	165,800,000
Indefinite-life intangibles	180,600,000	173,400,000
Total intangibles, cost	663,400,000	633,800,000
Total intangibles, net	325,900,000	339,200,000
Customer relationships
Acquired Intangible Assets by Major Class [Line Items]
Finite-life intangibles, cost	435,900,000	418,100,000
Accumulated amortization	(308,100,000)	(269,100,000)
Finite-life intangibles, net	127,800,000	149,000,000.0
Proprietary technology and patents
Acquired Intangible Assets by Major Class [Line Items]
Finite-life intangibles, cost	46,900,000	42,300,000
Accumulated amortization	(29,400,000)	(25,500,000)
Finite-life intangibles, net	$ 17,500,000	$ 16,800,000