Business segment information - Operating Income (Loss) by GBU (Parenthetical) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Product Type Reporting Information [Line Items]
Charges related to U.S. Government resolutions	$ (83,178,000)	$ 89,101,000
Spine [Member]
Product Type Reporting Information [Line Items]
Charges related to U.S. Government resolutions		43,100,000
Orthopedics [Member]
Product Type Reporting Information [Line Items]
Charges related to U.S. Government resolutions		6,500,000
Corporate [Member]
Product Type Reporting Information [Line Items]
Charges related to U.S. Government resolutions		7,500,000
Senior management succession charges		$ 3,200,000