Earnings Per Share - Calculation of EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share [Abstract]
Net income attributable to Amkor common stockholders, basic	$ 45,351	$ 170,663
Net income attributable to Amkor common stockholders, diluted	$ 45,351	$ 170,663
Weighted-average number of common shares outstanding - basic (in shares)	245,330	244,403
Effect of dilutive securities:
Share-based awards (in shares)	1,757	1,597
Weighted-average number of common shares outstanding - diluted (in shares)	247,087	246,000
Net income attributable to Amkor per common share:
Basic (in dollars per share)	$ 0.18	$ 0.70
Diluted (in dollars per share)	$ 0.18	$ 0.69