Document and Entity Information	9 Months Ended
	Sep. 30, 2017 shares
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Trading Symbol	SYNT
Entity Registrant Name	SYNTEL INC
Entity Central Index Key	0001040426
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	82,853,897