Net Sales and Profit by Reportable Segment (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
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue, net	$ 210,170	$ 196,185	$ 193,329	$ 181,041	$ 406,355	$ 374,370
Segment profit	71,938	68,863	67,252	63,274	140,801	130,526
Amortization	(4,647)	(4,720)	(4,050)	(3,011)	(9,367)	(7,061)
Corporate and other	(49,270)	(46,676)	(55,202)	(39,391)	(95,946)	(94,593)
Operating income	18,021	17,467	8,000	20,872	35,488	28,872
U S Neurosurgery
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue, net	42,324	40,183	41,316	38,130	82,507	79,446
Segment profit	21,890	21,156	20,708	19,157	43,046	39,865
U S Instruments
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue, net	41,269	37,994	37,836	37,553	79,263	75,389
Segment profit	9,440	7,526	7,452	5,798	16,966	13,250
U.S. Extremities
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue, net	32,048	26,587	23,210	21,306	58,635	44,516
Segment profit	13,305	9,183	9,853	8,182	22,488	18,035
U.S. Spine And Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue, net	48,823	44,810	43,267	37,325	93,633	80,592
Segment profit	13,862	13,533	12,461	12,725	27,395	25,186
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue, net	45,706	46,611	47,700	46,727	92,317	94,427
Segment profit	$ 13,441	$ 17,465	$ 16,778	$ 17,412	$ 30,906	$ 34,190