(Loss) earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net (loss) income attributable to Stewart	$ (8,190)	$ 57,897
Denominator (000):
Basic average shares outstanding (in shares)	27,201	26,960
Diluted average shares outstanding (in shares)	27,201	27,444
Basic (loss) earnings per share attributable to Stewart (in usd per share)	$ (0.30)	$ 2.15
Diluted (loss) earnings per share attributable to Stewart (in usd per share)	$ (0.30)	$ 2.11
Stock options
Denominator (000):
Average number of dilutive shares relating to options and grants of restricted shares and units (in shares)	0	265
Restricted stock and restricted stock units
Denominator (000):
Average number of dilutive shares relating to options and grants of restricted shares and units (in shares)	0	219