Cover Page - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	001-02658
Entity Registrant Name	STEWART INFORMATION SERVICES CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	74-1677330
Entity Address, Address Line One	1360 Post Oak Blvd.,
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Houston,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77056
City Area Code	713
Local Phone Number	625-8100
Title of 12(b) Security	Common Stock, $1 par value per share
Trading Symbol	STC
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		23,712,238
Entity Central Index Key	0000094344
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false