v3.8.0.1
DOCUMENT AND ENTITY INFORMATION - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Feb. 21, 2018
Jun. 30, 2017
Entity [Abstract]      
Entity Registrant Name K2M Group Holdings, Inc.    
Entity Central Index Key 0001499807    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Document Type 10-K    
Document Period End Date Dec. 31, 2017    
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   43,387,803  
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 1,000