Acquisitions (Provisional Amount Of Goodwill Recognized) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010	Mar. 31, 2011 Whitehall Group [Member]
Business Acquisition [Line Items]
Fair value of previously held interest			$ 250,156
Consideration paid for the remaining shares in Whitehall			75,713
Less: Net identifiable assets and liabilities			(56,314)
Goodwill on acquisition	$ 1,064,729	$ 1,450,273	$ 269,555

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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