Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net income attributable to Stewart	$ 19,306	$ 22,378	$ 12,540	$ 18,598
Denominator (000):
Basic average shares outstanding	23,614	23,546	23,605	23,527
Average number of dilutive shares relating to grants of restricted shares and units	144	79	145	80
Basic and diluted average shares outstanding	23,758	23,625	23,750	23,607
Basic earnings per share attribute to Stewart (in usd per share)	$ 0.82	$ 0.95	$ 0.53	$ 0.79
Diluted earnings per share attribute to Stewart (in usd per share)	$ 0.81	$ 0.95	$ 0.53	$ 0.79