Business segment information (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Market sector information
Total Net Sales	$ 151,525	$ 144,747	$ 143,551	$ 139,165	$ 143,796	$ 138,906	$ 142,845	$ 138,823	$ 578,988	$ 564,370	$ 545,635
Percent of Total Net Sales									100.00%	100.00%	100.00%
Strategic Products
Market sector information
Total Net Sales									573,161	551,093	515,175
Percent of Total Net Sales									99.00%	98.00%	94.00%
Spine Products
Market sector information
Total Net Sales									304,217	306,404	279,425
Percent of Total Net Sales									52.00%	54.00%	51.00%
Implants and Biologics
Market sector information
Total Net Sales									143,775	133,831	120,445
Percent of Total Net Sales									24.00%	23.00%	22.00%
Stimulation
Market sector information
Total Net Sales									160,442	172,573	158,980
Percent of Total Net Sales									28.00%	31.00%	29.00%
Orthopedics Products
Market sector information
Total Net Sales									165,904	149,175	139,304
Percent of Total Net Sales									29.00%	26.00%	25.00%
Sports Medicine Products
Market sector information
Total Net Sales									103,040	95,514	96,446
Percent of Total Net Sales									18.00%	18.00%	18.00%
Divested Products
Market sector information
Total Net Sales									$ 5,827	$ 13,277	$ 30,460
Percent of Total Net Sales									1.00%	2.00%	6.00%