Note 15 Income Per Share

The Company calculates income per share under the two-class method, as certain non-vested share awards contain non-forfeitable rights to dividends. As such, these awards are considered securities that participate in the earnings of the Company. Non-vested shares are discussed further in note 12.

The Company had 30,479,969 and 26,715,532 shares of Class A common stock outstanding as of March 31, 2018 and 2017, respectively, exclusive of issued non-vested restricted shares. Certain stock options and non-vested restricted shares are potentially dilutive securities, but are not included in the calculation of diluted income per share because to do so would have been anti-dilutive for the three months ended March 31, 2018 and 2017.

The following table illustrates the computation of basic and diluted income per share for the three months ended March 31, 2018 and 2017:


	For the three months ended
	March 31, 2018		March 31, 2017
Net income	$	8,464	$	8,258
Less: income allocated to participating securities		(13)		(8)
Income allocated to common shareholders	$	8,451	$	8,250
Weighted average shares outstanding for basic income per common share		30,493,689		26,801,773
Dilutive effect of equity awards		649,839		844,473
Dilutive effect of warrants		—		33,783
Weighted average shares outstanding for diluted income per common share		31,143,528		27,680,029
Basic income per share	$	0.28	$	0.31
Diluted income per share	$	0.27	$	0.30

The Company had 1,516,044 and 1,719,701 outstanding stock options to purchase common stock at weighted average exercise prices of $21.89 and $20.56 per share at March 31, 2018 and 2017, respectively, which have time-vesting criteria, and as such, any dilution is derived only for the time frame in which the vesting criteria had been met and where the inclusion of those stock options is dilutive. Additionally, 250,750 warrants were exercised in a non-cash transaction during the first quarter of 2017, representing the remaining outstanding warrants to purchase shares of the Company’s common stock. The warrants had an exercise price of $20.00. The Company had 418,638 and 490,528 unvested restricted shares and units issued as of March 31, 2018 and 2017, respectively, which have performance, market and/or time-vesting criteria, and as such, any dilution is derived only for the time frame in which the vesting criteria had been met and where the inclusion of those restricted shares and units is dilutive.