Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Computation of basic and diluted earnings per share

The following table summarizes the computation of basic and diluted EPS:

	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2018		2017		2018		2017
	(In thousands, except per share data)
Net income attributable to Amkor common stockholders	$	56,662	$	59,264	$	98,797	$	163,491
Weighted-average number of common shares outstanding — basic	239,370		239,068		239,312		238,873
Effect of dilutive securities:
Stock options and restricted share awards	396		572		471		737
Weighted-average number of common shares outstanding — diluted	239,766		239,640		239,783		239,610
Net income attributable to Amkor per common share:
Basic	$	0.24	$	0.25	$	0.41	$	0.68
Diluted	0.24		0.25		0.41		0.68

Summary of potential shares of common stock excluded from diluted earnings per share

The following table summarizes the potential shares of common stock that were excluded from diluted EPS, because the effect of including these potential shares was anti-dilutive:

	For the Three Months Ended September 30,		For the Nine Months Ended September 30,
	2018	2017	2018	2017
	(In thousands)
Stock options and restricted share awards	3,656	3,483	3,544	3,463