Goodwill And Other Intangible Assets (Rollforward Of Goodwill And Other Intangible Assets) (Detail) (USD $)	9 Months Ended
	Sep. 30, 2012
Goodwill and Other Intangible Assets [Roll Forward]
Goodwill, beginning balance	$ 714,772,000
Other intangible assets, non-amortizing, beginning balance	66,200,000
Other intangible assets, amortizing, beginning balance	44,500,000	[1]
Goodwill and other intangible assets, beginning balance	825,479,000
Accruals of acquisition-related contingent consideration	9,500,000
Amortization expense	(8,400,000)
Goodwill, ending balance	724,347,000
Other intangible assets, non-amortizing, ending balance	66,200,000
Other intangible assets, amortizing, ending balance	36,100,000	[1]
Goodwill and other intangible assets, ending balance	$ 826,576,000

[1] Consists principally of customer relationships, trade names and non-compete agreements with finite lives.