Changes to Contingent Consideration (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration, beginning balance				$ 16,450	$ 16,450
Increases due to acquisitions					13,264
Decreases due to payments					(11,535)
Changes due to currency fluctuations					(1,037)
Changes in fair value reflected in income statement (SG&A)	(5,081)	0	0	(2,140)	(7,221)	0	0
Contingent consideration, ending balance	$ 9,921				$ 9,921	$ 16,450