Changes in Carrying Amount of Goodwill (Detail) (USD $) In Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2011	Dec. 31, 2010
Goodwill [Line Items]
Beginning Balance	$ 1,595,764	$ 1,394,091
Goodwill acquired during year	354,355	203,003
Changes in goodwill on 2010 acquisitions	(8,575)
Sale of assets	(2,887)	(2,345)
Changes due to currency fluctuation	(13,668)	1,015
Ending Balance	1,924,989	1,595,764
United States
Goodwill [Line Items]
Beginning Balance	1,279,758	1,153,149
Goodwill acquired during year	229,994	128,954
Changes in goodwill on 2010 acquisitions	(803)
Sale of assets	0	(2,345)
Changes due to currency fluctuation	0	0
Ending Balance	1,508,949	1,279,758
Foreign Countries
Goodwill [Line Items]
Beginning Balance	316,006	240,942
Goodwill acquired during year	124,361	74,049
Changes in goodwill on 2010 acquisitions	(7,772)
Sale of assets	(2,887)	0
Changes due to currency fluctuation	(13,668)	1,015
Ending Balance	$ 416,040	$ 316,006

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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+ Details

- Definition

The increase (decrease) in the recorded value of goodwill for foreign currency translation adjustments and purchase accounting adjustments needed to revise the carrying amount of goodwill to fair value.

+ References

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

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