Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Total Amkor Stockholders’ Equity	Common Stock	Additional Paid- In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interest in Subsidiaries
Balance at beginning of period, common stock (in shares) at Dec. 31, 2021			290,466
Balance at beginning of period at Dec. 31, 2021	$ 2,972,546	$ 2,942,276	$ 290	$ 1,977,134	$ 1,163,939	$ 19,978	$ (219,065)	$ 30,270
Balance at beginning of period, treasury stock (in shares) at Mar. 31, 2022							(46,155)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	171,228	170,663			170,663			565
Other comprehensive income (loss)	(9,482)	(9,482)				(9,482)
Treasury stock acquired through surrender of shares for tax withholding (in shares)							(4)
Treasury stock acquired through surrender of shares for tax withholding	(82)	(82)					$ (82)
Issuance of stock through share-based compensation plans (in shares)			221
Issuance of stock through share-based compensation plans	1,483	1,483	$ 1	1,482
Share-based compensation	3,497	3,497		3,497
Cash dividends declared	(12,232)	(12,232)			(12,232)
Subsidiary dividends to non-controlling interests	(136)							(136)
Balance at end of period, common stock (in shares) at Mar. 31, 2022			290,687
Balance at end of period at Mar. 31, 2022	$ 3,126,822	3,096,123	$ 291	1,982,113	1,322,370	10,496	$ (219,147)	30,699
Balance at end of period, treasury stock (in shares) at Dec. 31, 2021							(46,151)
Balance at beginning of period, common stock (in shares) at Dec. 31, 2022	245,091		291,249
Balance at beginning of period at Dec. 31, 2022	$ 3,699,701	3,668,752	$ 291	1,996,344	1,874,644	16,699	$ (219,226)	30,949
Balance at beginning of period, treasury stock (in shares) at Mar. 31, 2023	(46,269)						(46,269)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 45,224	45,351			45,351			(127)
Other comprehensive income (loss)	(1,609)	(1,609)				(1,609)
Treasury stock acquired through surrender of shares for tax withholding (in shares)							(111)
Treasury stock acquired through surrender of shares for tax withholding	(2,823)	(2,823)					$ (2,823)
Issuance of stock through share-based compensation plans (in shares)			565
Issuance of stock through share-based compensation plans	1,524	1,524	$ 1	1,523
Share-based compensation	3,708	3,708		3,708
Cash dividends declared	(18,426)	(18,426)			(18,426)
Subsidiary dividends to non-controlling interests	$ (136)							(136)
Balance at end of period, common stock (in shares) at Mar. 31, 2023	245,545		291,814
Balance at end of period at Mar. 31, 2023	$ 3,727,163	$ 3,696,477	$ 292	$ 2,001,575	$ 1,901,569	$ 15,090	$ (222,049)	$ 30,686
Balance at end of period, treasury stock (in shares) at Dec. 31, 2022	(46,158)						(46,158)