Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2011	Dec. 31, 2010
Amkor stockholders' equity:
Preferred stock designated Series A, par value	$ 0.001	$ 0.001
Preferred stock designated Series A, shares authorized	10,000,000	10,000,000
Preferred stock designated Series A, shares issued	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	197,359,000	183,467,000
Common stock, shares outstanding	168,628,000	183,420,000
Treasury stock, shares	28,731,000	47,000