Summary of Acquisition Location (Detail)	12 Months Ended
	Dec. 31, 2012 Entity	Dec. 31, 2011 Entity	Dec. 31, 2010 Entity
Business Acquisition [Line Items]
Number of acquisitions completed	41	45	33
United States
Business Acquisition [Line Items]
Number of acquisitions completed	17	21	13
Argentina
Business Acquisition [Line Items]
Number of acquisitions completed	1	1	1
Brazil
Business Acquisition [Line Items]
Number of acquisitions completed	1	4	3
Canada
Business Acquisition [Line Items]
Number of acquisitions completed	0	2	0
Chile
Business Acquisition [Line Items]
Number of acquisitions completed	3	1	1
Ireland
Business Acquisition [Line Items]
Number of acquisitions completed	0	1	0
Japan
Business Acquisition [Line Items]
Number of acquisitions completed	1	3	2
Mexico
Business Acquisition [Line Items]
Number of acquisitions completed	2	0	3
Portugal
Business Acquisition [Line Items]
Number of acquisitions completed	1	1	1
Romania
Business Acquisition [Line Items]
Number of acquisitions completed	2	6	1
Spain
Business Acquisition [Line Items]
Number of acquisitions completed	8	2	0
United Kingdom
Business Acquisition [Line Items]
Number of acquisitions completed	5	3	8