Goodwill and Other Intangible Assets (Weighted Average Amortization Period by Intangible Asset Class) (Detail)	12 Months Ended
	Dec. 31, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	5 years 5 months 12 days
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	6 years 1 month 6 days
Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	3 years 10 months 24 days
Trademarks and trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	4 years 10 months 6 days
Covenants not to compete
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	1 year 3 months 7 days