Consolidated Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Total Amkor Stockholders' Equity [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock [Member]	Noncontrolling Interest in Subsidiaries [Member]
Balance at beginning of period, shares at Dec. 31, 2012			197,709
Balance at beginning of period, shares at Dec. 31, 2012							45,312
Balance at beginning of period at Dec. 31, 2012	$ 666,794	$ 657,955	$ 198	$ 1,614,143	$ (756,644)	$ 11,241	$ (210,983)	$ 8,839
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	111,657						0
Net Income (Loss) Attributable to Parent	109,296	109,296			109,296
Net Income (Loss) Attributable to Noncontrolling Interest	2,361							2,361
Other comprehensive income	(11,496)	(11,496)				(11,496)		0
Conversion of debt to common stock	195,034	195,034	$ 64	194,970
Conversion of debt to common stock, shares			64,027
Treasury stock acquired through surrender of shares for tax withholding	(466)	(466)					$ (466)
Treasury stock acquired through surrender of shares for tax withholding, shares							(95)
Issuance of stock through share-based compensation plans	446	446		446
Issuance of stock through share-based compensation plans, shares			373
Share-based compensation	2,971	2,971		2,971
Subsidiary dividends paid to noncontrolling interest	0
Balance at end of period, shares at Dec. 31, 2013			262,109
Balance at end of period, shares at Dec. 31, 2013							45,407
Balance at end of period at Dec. 31, 2013	964,940	953,740	$ 262	1,812,530	(647,348)	(255)	$ (211,449)	11,200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	133,887		0				$ 0
Net Income (Loss) Attributable to Parent	130,386	130,386			130,386
Net Income (Loss) Attributable to Noncontrolling Interest	3,501							3,501
Other comprehensive income	(32,612)	(32,612)				(32,612)		0
Conversion of debt to common stock	56,350	56,350	$ 19	56,331
Conversion of debt to common stock, shares			18,632				0
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
Subsidiary dividends paid to noncontrolling interest	$ 0
Balance at end of period, shares at Dec. 31, 2014	282,231		282,231
Balance at end of period, shares at Dec. 31, 2014	45,604						45,604
Balance at end of period at Dec. 31, 2014	$ 1,130,936	1,116,235	$ 282	1,878,810	(516,962)	(32,867)	$ (213,028)	14,701
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	59,607		0	0			0
Net Income (Loss) Attributable to Parent	56,812	56,812			56,812
Net Income (Loss) Attributable to Noncontrolling Interest	2,795							2,795
Other comprehensive income	30,783	30,783				30,783		0
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)	0	$ 0	0	0	0	$ 0	(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	$ 1,225,133	$ 1,207,883	$ 283	$ 1,883,592	$ (460,150)	$ (2,084)	$ (213,758)	$ 17,250