Consolidated Statement of Stockholders' Equity (USD $) In Thousands, unless otherwise specified	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 at Dec. 31, 2011	$ 701,221	$ 693,266	$ 197	$ 1,611,242	$ (798,462)	$ 10,849	$ (130,560)	$ 7,955
Balance at beginning of period, shares at Dec. 31, 2011			197,359
Treasury Stock, Shares							(45,312)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	42,702
Net Income (Loss) Attributable to Parent	41,818	41,818	0		41,818		0
Net Income (Loss) Attributable to Noncontrolling Interest	(884)							884
Other comprehensive income	392	392				392
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest								0
Repurchase of common stock	(79,814)	(79,814)					(79,814)
Repurchase of common stock, number of shares							(16,472)
Treasury stock acquired through surrender of shares for tax withholding	(609)	(609)					(609)
Treasury stock acquired through surrender of shares for tax withholding, shares							(109)
Issuance of stock through share-based compensation plans	(182)	(182)	(1)	(181)
Issuance of stock through share-based compensation plans, shares			350
Share-based compensation expense	(2,720)	(2,720)		(2,720)
Balance at end of period at Dec. 31, 2012	666,794	657,955	198	1,614,143	(756,644)	11,241	(210,983)	8,839
Balance at end of period, shares at Dec. 31, 2012			197,709
Treasury Stock, Shares	(45,407)						(45,407)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	111,657
Net Income (Loss) Attributable to Parent	109,296	109,296	0		109,296		0
Net Income (Loss) Attributable to Noncontrolling Interest	(2,361)							2,361
Other comprehensive income	(11,496)	(11,496)				(11,496)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest								0
Conversion of debt to common stock	195,034	195,034	64	194,970
Conversion of debt to common stock, shares			64,027				0
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 expense	(2,971)	(2,971)		(2,971)
Balance at end of period at Dec. 31, 2013	964,940	953,740	262	1,812,530	(647,348)	(255)	(211,449)	11,200
Balance at end of period, shares at Dec. 31, 2013	262,109		262,109
Treasury Stock, Shares	(45,604)						(45,604)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	133,887
Net Income (Loss) Attributable to Parent	130,386	130,386	0	0	130,386		0
Net Income (Loss) Attributable to Noncontrolling Interest	(3,501)							3,501
Other comprehensive income	(32,612)	(32,612)				(32,612)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest								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 expense	(3,700)	(3,700)
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
Balance at end of period, shares at Dec. 31, 2014	282,231		282,231