Earnings Per Share

Basic earnings (loss) per share are based on the weighted average number of shares of common stock outstanding. Diluted earnings per share are based upon the weighted average number of shares of common stock outstanding plus all potentially dilutive securities that were assumed to be converted into common shares at the beginning of the period under the treasury stock method. This method requires that the effect of potentially dilutive common stock equivalents be excluded from the calculation of diluted earnings per share for the periods in which net losses are reported because the effect is anti-dilutive.

The following table reconciles the number of common shares used in calculating the basic and diluted net earnings per share:



	December 31,
(In thousands - except per share data)	2019			2018			2017
Basic average common shares outstanding¹	16,533			16,487			16,464
Incremental shares due to:
Restricted stock units	—			—			22
Performance shares	—			—			45
Stock options	—			—			25
Diluted average common shares outstanding	16,533			16,487			16,556
Basic net income (loss) per common share	$	(0.34	)	$	(8.72	)	$	5.91
Diluted net income (loss) per common share	$	(0.34	)	$	(8.72	)	$	5.88

Anti-dilutive shares excluded from the calculation were 1.0 million, 0.9 million and 0.5 million for the years ended December 31, 2019, 2018 and 2017.

1Basic average common shares outstanding include restricted stock awards that are fully vested, but are deferred for future issuance. See Note 14 "Stockholders' Equity" for further discussion.