Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Net sales	$ 1,152,616	$ 894,964
Cost of sales	963,708	774,203
Gross profit	188,908	120,761
Selling, general and administrative	72,582	71,587
Research and development	32,253	35,754
Total operating expenses	104,835	107,341
Operating income	84,073	13,420
Interest expense	17,045	19,273
Other (income) expense, net	(2,315)	(4,565)
Total other expense, net	14,730	14,708
Income (loss) before taxes	69,343	(1,288)
Income tax expense	4,846	21,380
Net income (loss)	64,497	(22,668)
Net income attributable to non-controlling interests	(608)	(211)
Net income (loss) attributable to Amkor	$ 63,889	$ (22,879)
Net income (loss) attributable to Amkor per common share:
Basic (in dollars per share)	$ 0.27	$ (0.10)
Diluted (in dollars per share)	$ 0.26	$ (0.10)
Shares used in computing per common share amounts:
Basic (in shares)	240,919	239,414
Diluted (in shares)	241,333	239,414