Business Segment, Product, and Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 segment	Mar. 31, 2013
Segment Reporting [Abstract]
Number of Reportable Segments	1
Revenue from spine surgery product line offerings
Total revenues	$ 177,496	$ 159,504
Spine Surgery Products [Member]
Revenue from spine surgery product line offerings
Total revenues	137,308	122,667
Biologics [Member]
Revenue from spine surgery product line offerings
Total revenues	29,489	27,156
Monitoring Service [Member]
Revenue from spine surgery product line offerings
Total revenues	$ 10,699	$ 9,681