Earnings Per Share - Basic (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income attributable to shareholders of Criteo S.A.	$ 5,716	$ 10,823	$ 21,175	$ 29,943
Weighted average number of shares outstanding (in shares)	61,415,467	64,581,476	61,553,875	64,459,867
Basic earnings per share (in USD per share)	$ 0.09	$ 0.17	$ 0.34	$ 0.46