Goodwill And Intangible Assets (Changes In Carrying Amount Of Goodwill) (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Goodwill And Intangible Assets
Balance, beginning of period	$ 964,970	$ 859,759	$ 894,497	$ 813,876
Goodwill acquired, including post acquisition adjustments	186,735	14,053	261,975	59,936
Disposals	0	(15)	(4,767)	(15)
Balance, end of period	$ 1,151,705	$ 873,797	$ 1,151,705	$ 873,797

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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