Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net sales	$ 894,964	$ 1,025,319
Cost of sales	774,203	867,548
Gross profit	120,761	157,771
Selling, general and administrative	71,587	80,723
Research and development	35,754	40,929
Total operating expenses	107,341	121,652
Operating income	13,420	36,119
Interest expense	19,273	20,011
Other (income) expense, net	(4,565)	3,432
Total other expense, net	14,708	23,443
Income (loss) before taxes	(1,288)	12,676
Income tax expense	21,380	2,481
Net income (loss)	(22,668)	10,195
Net income attributable to non-controlling interests	(211)	(651)
Net income (loss) attributable to Amkor	$ (22,879)	$ 9,544
Net income (loss) attributable to Amkor per common share:
Basic (in dollars per share)	$ (0.10)	$ 0.04
Diluted (in dollars per share)	$ (0.10)	$ 0.04
Shares used in computing per common share amounts:
Basic (in shares)	239,414	239,214
Diluted (in shares)	239,414	239,816