Summary of Acquisition Location (Detail)	3 Months Ended
	Mar. 31, 2012 Entity
Business Acquisition [Line Items]
Number of acquisitions completed	11
United States
Business Acquisition [Line Items]
Number of acquisitions completed	6
Japan
Business Acquisition [Line Items]
Number of acquisitions completed	1
Romania
Business Acquisition [Line Items]
Number of acquisitions completed	1
Spain
Business Acquisition [Line Items]
Number of acquisitions completed	3