Document and Entity Information - shares
3 Months Ended
Mar. 31, 2019
Apr. 26, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Entity Registrant Name EXLSERVICE HOLDINGS, INC.  
Entity Central Index Key 0001297989  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Document Period End Date Mar. 31, 2019  
Document Fiscal Year Focus 2019  
Trading Symbol EXLS  
Document Fiscal Period Focus Q1  
Entity Emerging Growth Company false  
Entity Small Business false  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   34,341,972