Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales	$ 1,354,023	$ 1,083,917	$ 3,679,548	$ 2,874,186
Cost of sales	1,112,938	901,677	3,057,235	2,447,731
Gross profit	241,085	182,240	622,313	426,455
Selling, general and administrative	77,781	70,458	224,623	206,803
Research and development	35,835	32,927	99,624	104,867
Total operating expenses	113,616	103,385	324,247	311,670
Operating income	127,469	78,855	298,066	114,785
Interest expense	16,404	16,988	49,461	54,914
Other (income) expense, net	2,415	(1,760)	1,567	641
Total other expense, net	18,819	15,228	51,028	55,555
Income before taxes	108,650	63,627	247,038	59,230
Income tax expense	15,753	9,141	33,504	36,418
Net income	92,897	54,486	213,534	22,812
Net income attributable to non-controlling interests	(746)	(416)	(2,070)	(1,071)
Net income attributable to Amkor	$ 92,151	$ 54,070	$ 211,464	$ 21,741
Net income attributable to Amkor per common share:
Basic (in dollars per share)	$ 0.38	$ 0.23	$ 0.88	$ 0.09
Diluted (in dollars per share)	$ 0.38	$ 0.23	$ 0.87	$ 0.09
Shares used in computing per common share amounts:
Basic (in shares)	241,675	239,586	241,232	239,503
Diluted (in shares)	242,592	239,937	241,937	239,858