9. Earnings Per Share

Basic earnings per common share is computed by dividing net income by the weighted average number of common shares outstanding for the period. Treasury stock is excluded from the weighted average number of shares of common stock outstanding. Diluted earnings per share attributable to common stockholders is computed based on the weighted average number of shares of common stock and dilutive securities outstanding during the period. Dilutive securities are common stock equivalents that are freely exercisable into common stock at less than market prices or otherwise dilute earnings if converted. The net effect of common stock equivalents is based on the incremental common stock that would be issued upon the assumed exercise of common stock options and the vesting of restricted stock using the treasury stock method. Common stock equivalents are not included in diluted earnings per share when their inclusion is antidilutive. Additionally, redeemable preferred stock is not convertible and does not affect dilutive shares.

The computations of diluted weighted average earnings per common share do not include approximately 400, 700 and Nil restricted shares for the year ended December 31, 2018, 2017, and 2016, respectively, as the effect of their inclusion would have been antidilutive to earnings per share.

The following table presents the calculation of basic and diluted EPS:


	Years Ended December 31,
	2018		2017		2016
		(in thousands)
Net income attributable to common shareholders	$	39,898	$	60,299	$	13,780

Basic weighted average common shares outstanding		5,915		6,074		6,570
Potentially dilutive common shares		131		146		144
Diluted weighted average common shares outstanding		6,046		6,220		6,714

Basic weighted average earnings per common share	$	6.75	$	9.93	$	2.10
Diluted weighted average earnings per common share	$	6.60	$	9.69	$	2.05