Earnings Per Share (Calculation of EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Net income attributable to Amkor common stockholders, basic	$ 359,813	$ 765,823	$ 642,995
Net income attributable to Amkor common stockholders, diluted	$ 359,813	$ 765,823	$ 642,995
Weighted-average number of common shares outstanding — basic (in shares)	245,628	244,676	243,878
Effect of dilutive securities:
Share-based awards (in shares)	1,548	1,529	1,826
Weighted-average number of common shares outstanding — diluted (in shares)	247,176	246,205	245,704
Net income attributable to Amkor per common share:
Basic (in dollars per share)	$ 1.46	$ 3.13	$ 2.64
Diluted (in dollars per share)	$ 1.46	$ 3.11	$ 2.62