EARNINGS PER SHARE

Share-based awards that contain non-forfeitable rights to dividends or dividend equivalents, whether paid or unpaid, are participating securities and included in the computation of both basic and diluted earnings per share. Our grants of restricted stock awards to our employees and directors are considered participating securities and we have prepared our earnings per share calculations to exclude outstanding unvested restricted stock awards, using the two-class method, in the basic and diluted weighted average shares outstanding calculation.

The following table sets forth the computation of the basic and diluted earnings per share for the years ended December 31, 2015, 2016 and 2017 (in thousands, except per share data):



	Year Ended December 31,
	2015			2016			2017
Numerator for basic and diluted earnings per share:
Net income	$	20,853		$	19,581		$	37,193
Less: Earnings allocated to unvested restricted stock	(257		)	(89		)	(135		)
Income attributable to common stockholders	$	20,596		$	19,492		$	37,058

Denominator:
Denominator for basic earnings per common share - weighted average shares outstanding	17,791			16,515			16,438
Effect of dilutive securities:
Stock options	246			454			336
Convertible subordinated notes	276			491			941
Denominator for diluted earnings per common share - weighted average shares outstanding	18,313			17,460			17,715

Basic earnings per common share	$	1.16		$	1.18		$	2.25
Diluted earnings per common share	$	1.12		$	1.12		$	2.09

The fully diluted weighted average shares outstanding for the years ended December 31, 2015, 2016 and 2017, and the corresponding calculation of fully diluted earnings per share, included approximately 0.3 million, 0.5 million and 0.9 million shares that would have been issued upon the conversion of our convertible subordinated notes as a result of the application of the if-converted method prescribed by the FASB ASC 260.

For the year ended December 31, 2017, approximately 354,000 stock options were excluded from the computation of diluted earnings per share because the inclusion of such stock options would result in an antidilutive effect. There were no options excluded in the computation of diluted earnings per share for the years ended December 31, 2015 and 2016.