Document and Entity Information
12 Months Ended
Mar. 31, 2018
Document - Document and Entity Information [Abstract]  
Document Type 20-F
Amendment Flag false
Document Period End Date Mar. 31, 2018
Document Fiscal Year Focus 2018
Document Fiscal Period Focus FY
Trading Symbol WNS
Entity Registrant Name WNS (HOLDINGS) LTD
Entity Central Index Key 0001356570
Current Fiscal Year End Date --03-31
Entity Well-known Seasoned Issuer Yes
Entity Current Reporting Status Yes
Entity Filer Category Large Accelerated Filer
Entity Common Stock, Shares Outstanding 50,434,080