Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Apr. 30, 2009
Dilutive Securities Adjustments [Line Items]
Net income attributable to Amkor	$ 49,521	$ 29,727	$ 70,154	$ 43,109
Income allocated to participating securities	(184)	(251)	(269)	(374)
Net income available to Amkor common stockholders — basic	49,337	29,476	69,885	42,735
Adjustment for dilutive securities on net income:
Net income reallocated to participating securities	3	58	9	80
Net income attributable to Amkor — diluted	49,472	33,143	70,933	50,441
Weighted average shares outstanding — basic	232,891	160,886	224,868	156,672
Effect of dilutive securities:
Stock options	1,115	10	609	14
Weighted average shares outstanding — diluted	236,872	235,111	236,182	235,099
Net income attributable to Amkor per common share:
Basic (in dollars per share)	$ 0.21	$ 0.18	$ 0.31	$ 0.27
Diluted (in dollars per share)	$ 0.21	$ 0.14	$ 0.30	$ 0.21
Convertible Senior Subordinated Notes Due April 2014 [Member]
Adjustment for dilutive securities on net income:
Interest on 6.0% convertible notes due 2014, net of tax	$ 132	$ 3,609	$ 1,039	$ 7,626
Effect of dilutive securities:
6.0% convertible notes due 2014	2,866	74,215	10,705	78,413
Net income attributable to Amkor per common share:
Interest rate on convertible notes due 2014	6.00%	6.00%	6.00%	6.00%	6.00%