Earnings per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net income attributable to Stewart	$ 18,568	$ 23,599	$ 22,657	$ 12,404
Less: Cash paid on Class B Common Shares conversion	0	(12,000)	0	(12,000)
Net income available to common shareholders	$ 18,568	$ 11,599	$ 22,657	$ 404
Denominator (000):
Basic average shares outstanding	23,444	23,365	23,438	23,357
Diluted average shares outstanding	23,620	23,559	23,613	23,542
Basic earnings per share attributable to Stewart (in usd per share)	$ 0.79	$ 0.50	$ 0.97	$ 0.02
Diluted earnings per share attributable to Stewart (in usd per share)	$ 0.79	$ 0.49	$ 0.96	$ 0.02
Options
Denominator (000):
Average number of dilutive shares relating to share-based incentives	0	1	0	1
Restricted Shares
Denominator (000):
Average number of dilutive shares relating to share-based incentives	176	193	175	184