Change In Acquisition-Related Contingent Consideration Liability (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Business Acquisition, Contingent Consideration [Line Items]
Beginning balance	$ 16,426		$ 14,990
Acquisitions	(848)	[1]
Change in amount of contingent consideration	(731)		(557)
Payments			(370)
Ending balance	16,296		15,276
Fair Value Adjustment
Business Acquisition, Contingent Consideration [Line Items]
Change in amount of contingent consideration	731	[2]	557	[2]
Foreign Currency Translation
Business Acquisition, Contingent Consideration [Line Items]
Change in amount of contingent consideration	$ (13)		$ 99

[1] Includes adjustments during the purchase price allocation period.

[2] Adjustments to fair value related to accretion and remeasurement of contingent consideration are recorded in "Acquisition-related contingent consideration" on the Condensed Consolidated Statements of Comprehensive Income.