Document And Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Mar. 11, 2019
Jun. 30, 2018
Document And Entity Information [Abstract]      
Entity Registrant Name INNERWORKINGS INC    
Entity Central Index Key 0001350381    
Current Fiscal Year End Date --12-31    
Entity Filer Category Accelerated Filer    
Trading Symbol INWK    
Entity Common Stock, Shares Outstanding   52,271,946  
Document Type 10-K    
Amendment Flag false    
Amendment Description    
Document Period End Date Dec. 31, 2018    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2018    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 319,588,359
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false