Goodwill and Other Intangible Assets (Weighted Average Amortization Period by Intangible Asset Class) (Detail)	12 Months Ended
	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	6 years 7 months 2 days
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	7 years 6 months 19 days
Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	4 years 4 months 7 days
Trademarks and trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	5 years 11 days
Covenants not to compete
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	2 years 1 month 6 days