Changes in Carrying Amount of Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]
Beginning Balance	$ 1,913,703	$ 1,595,764
Goodwill acquired during year	21,585	353,600
Goodwill allocation adjustments	(23,323)	(11,114)
Sale of business		(2,887)
Changes due to currency fluctuation	12,275	(21,660)
Ending Balance	1,924,240	1,913,703
United States
Goodwill [Line Items]
Beginning Balance	1,506,416	1,279,758
Goodwill acquired during year	12,581	232,850
Goodwill allocation adjustments	(1,535)	(6,192)
Sale of business		0
Changes due to currency fluctuation	0	0
Ending Balance	1,517,462	1,506,416
International countries
Goodwill [Line Items]
Beginning Balance	407,287	316,006
Goodwill acquired during year	9,004	120,750
Goodwill allocation adjustments	(21,788)	(4,922)
Sale of business		(2,887)
Changes due to currency fluctuation	12,275	(21,660)
Ending Balance	$ 406,778	$ 407,287

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 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

- 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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Publisher FASB

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+ Details

- Definition

Write-off of the carrying amount of goodwill associated with all or a portion of a reporting unit that is sold in the period.

+ References+ Details