Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Total Amkor Stockholders' Equity	Common Stock	Additional Paid- In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interest in Subsidiaries
Balance at beginning of period, shares at Dec. 31, 2013			262,109
Balance at beginning of period, shares at Dec. 31, 2013							(45,407)
Balance at beginning of period at Dec. 31, 2013	$ 963,808	$ 952,608	$ 262	$ 1,812,530	$ (648,584)	$ (151)	$ (211,449)	$ 11,200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	133,240
Net income attributable to Amkor	129,739	129,739			129,739
Net Income (Loss) Attributable to Noncontrolling Interest	3,501							3,501
Total other comprehensive income (loss)	(32,320)	(32,320)				(32,320)
Conversion of debt to common stock	56,350	56,350	$ 19	56,331
Conversion of debt to common stock, shares			18,632
Treasury stock acquired through surrender of shares for tax withholding	(1,579)	(1,579)					$ (1,579)
Treasury stock acquired through surrender of shares for tax withholding, shares							(197)
Issuance of stock through share-based compensation plans	6,250	6,250	$ 1	6,249
Issuance of stock through share-based compensation plans, shares			1,490
Share-based compensation	3,700	3,700		3,700
Balance at end of period, shares at Dec. 31, 2014			282,231
Balance at end of period, shares at Dec. 31, 2014							(45,604)
Balance at end of period at Dec. 31, 2014	1,129,449	1,114,748	$ 282	1,878,810	(518,845)	(32,471)	$ (213,028)	14,701
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	53,893
Net income attributable to Amkor	51,098	51,098			51,098
Net Income (Loss) Attributable to Noncontrolling Interest	2,795							2,795
Total other comprehensive income (loss)	30,387	30,387				30,387
Treasury stock acquired through surrender of shares for tax withholding	(730)	(730)					$ (730)
Treasury stock acquired through surrender of shares for tax withholding, shares							(115)
Issuance of stock through share-based compensation plans	931	931	$ 1	930
Issuance of stock through share-based compensation plans, shares			493
Share-based compensation	3,852	3,852		3,852
Subsidiary dividends paid to noncontrolling interest	$ (246)							(246)
Balance at end of period, shares at Dec. 31, 2015	282,724		282,724
Balance at end of period, shares at Dec. 31, 2015	(45,719)						(45,719)
Balance at end of period at Dec. 31, 2015	$ 1,217,536	1,200,286	$ 283	1,883,592	(467,747)	(2,084)	$ (213,758)	17,250
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	167,304
Net income attributable to Amkor	164,190	164,190			164,190
Net Income (Loss) Attributable to Noncontrolling Interest	3,114							3,114
Total other comprehensive income (loss)	8,346	8,346				8,346
Treasury stock acquired through surrender of shares for tax withholding	(732)	(732)					$ (732)
Treasury stock acquired through surrender of shares for tax withholding, shares							(95)
Issuance of stock through share-based compensation plans	8,247	8,247	$ 1	8,246
Issuance of stock through share-based compensation plans, shares			1,755
Share-based compensation	3,251	3,251		3,251
Subsidiary dividends paid to noncontrolling interest	$ (548)							(548)
Balance at end of period, shares at Dec. 31, 2016	284,479		284,479
Balance at end of period, shares at Dec. 31, 2016	(45,814)						(45,814)
Balance at end of period at Dec. 31, 2016	$ 1,403,404	$ 1,383,588	$ 284	$ 1,895,089	$ (303,557)	$ 6,262	$ (214,490)	$ 19,816