Earnings Per Share - Basic (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income attributable to shareholders of Criteo S.A.	$ 5,227	$ 18,778	$ 26,402	$ 48,721
Weighted average number of shares outstanding (in shares)	60,080,598	64,868,545	61,059,345	64,600,869
Basic earnings per share (in USD per share)	$ 0.09	$ 0.29	$ 0.43	$ 0.75