Revenue by Major Product Category (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenue from External Customer [Line Items]
Total revenue, net	$ 210,170	$ 196,185	$ 193,329	$ 181,041	$ 406,355	$ 374,370
Orthopedics
Revenue from External Customer [Line Items]
Total revenue, net	95,695		81,479		181,847	153,731
Neurosurgery
Revenue from External Customer [Line Items]
Total revenue, net	67,775		68,174		133,832	133,361
Instruments
Revenue from External Customer [Line Items]
Total revenue, net	$ 46,700		$ 43,676		$ 90,676	$ 87,278