Goodwill And Other Intangible Assets (Schedule Of Carrying Amount Of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2012	Dec. 31, 2011
Goodwill And Other Intangible Assets [Abstract]
Goodwill, Beginning Balance	$ 369,811	$ 234,228
Goodwill acquired during the year		135,583
Goodwill adjustment to correct an immaterial error	(3,727)
Goodwill, Ending Balance	$ 366,084	$ 369,811

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Publisher FASB

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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+ Details

- Definition

The aggregate amount of goodwill acquired in the period and allocated to the reportable segment. The value is stated at fair value based on the purchase price allocation.

+ References+ Details