Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income attributable to Stewart	$ 57,897	$ 54,236
Denominator (000):
Basic average shares outstanding (in shares)	26,960	26,736
Diluted average shares outstanding (in shares)	27,444	26,984
Basic earnings per share attributable to Stewart (in usd per share)	$ 2.15	$ 2.03
Diluted earnings per share attributable to Stewart (in usd per share)	$ 2.11	$ 2.01
Stock options
Denominator (000):
Average number of dilutive shares relating to grants of restricted shares and units (in shares)	265	103
Restricted stock and restricted stock units
Denominator (000):
Average number of dilutive shares relating to grants of restricted shares and units (in shares)	219	145