Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 01, 2013 Common Stock	Nov. 01, 2013 Class B Common Stock
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Trading Symbol	STC
Entity Registrant Name	STEWART INFORMATION SERVICES CORP
Entity Central Index Key	0000094344
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		21,448,038	1,050,012