9. Earnings Per Share

Basic earnings per share is calculated by dividing income available to common shareholders by the weighted-average number of shares of common stock outstanding during each period. Diluted earnings per share (“diluted EPS”) is calculated using income available to common shareholders divided by diluted weighted-average shares of common stock outstanding during each period. Potentially dilutive securities include shares of common stock underlying SOSARs and non-vested stock awards (collectively “stock awards”). Diluted EPS considers the impact of potentially dilutive securities except in periods in which there is a loss because the inclusion of the potential common shares would have an anti-dilutive effect. Stock awards are excluded from the calculation of diluted EPS in the event they are subject to performance conditions or antidilutive. The following stock awards were excluded from the calculation of diluted EPS:



	Year ended December 31,
	2017		2016		2015
Stock awards subject to performance conditions		217		263		266
Stock awards that were antidilutive		1,695		1,316		289
Total stock awards excluded from diluted earnings per share		1,912		1,579		555

The following table sets forth the computations of basic and diluted earnings per share:



	Year ended December 31,
	2017		2016		2015
Net income	$	176,253	$	22,938	$	475,602
Shares:
Weighted average number of common shares outstanding		28,491		29,265		31,092
Dilutive stock awards		70		505		402
Diluted weighted average number of common shares outstanding		28,561		29,770		31,494
Basic earnings per share	$	6.19	$	0.78	$	15.30
Diluted earnings per share	$	6.17	$	0.77	$	15.10