Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 120,019	$ 64,497
Other comprehensive income (loss), net of tax:
Adjustments to net unrealized gains (losses) on available-for-sale debt investments	(32)	108
Adjustments to unrealized components of defined benefit pension plans	25	11
Foreign currency translation	(11,440)	475
Total other comprehensive income (loss)	(11,447)	594
Comprehensive income	108,572	65,091
Comprehensive income attributable to non-controlling interests	(210)	(608)
Comprehensive income attributable to Amkor	$ 108,362	$ 64,483