Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Dec. 31, 2015	Dec. 31, 2014
Amkor stockholders’ equity:
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	500,000	500,000
Common stock, shares issued (in shares)	282,724	282,231
Common stock, shares outstanding (in shares)	237,005	236,627
Preferred stock designated Series A, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock designated Series A, shares authorized (in shares)	10,000	10,000
Preferred stock designated Series A, shares issued (in shares)	0	0
Treasury stock, shares	45,719	45,604