Earnings Per Share - Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Net income attributable to Amkor common stockholders, basic	$ 58,897	$ 45,351
Net income attributable to Amkor common stockholders, diluted	$ 58,897	$ 45,351
Weighted-average number of common shares outstanding - basic (in shares)	246,008	245,330
Effect of dilutive securities:
Share-based awards (in shares)	1,606	1,757
Weighted-average number of common shares outstanding - diluted (in shares)	247,614	247,087
Net income attributable to Amkor per common share:
Basic (in dollars per share)	$ 0.24	$ 0.18
Diluted (in dollars per share)	$ 0.24	$ 0.18