SEGMENT AND GEOGRAPHIC INFORMATION (Revenue by Major Product Category) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue from External Customer [Line Items]
Total revenues	$ 252,176	$ 229,719	$ 231,351	$ 215,059	$ 220,769	$ 213,246	$ 205,547	$ 196,652	$ 928,305	$ 836,214	$ 830,871
Orthopedics
Revenue from External Customer [Line Items]
Total revenues									370,082	370,359	364,714
Neurosurgery
Revenue from External Customer [Line Items]
Total revenues									371,676	278,672	277,527
Instruments
Revenue from External Customer [Line Items]
Total revenues									$ 186,547	$ 187,183	$ 188,630