17. Net Income per Common Share

Basic earnings per common share is calculated based on the weighted average number of common shares outstanding for the period. Diluted earnings per common share is calculated based on the assumption that stock options outstanding, which have an exercise price less than the average market price of the Company’s common shares during the period, would have been exercised on the later of the beginning of the period or the date granted and that the funds obtained from the exercise were used to purchase common shares at the average market price during the period. All the Company’s restricted stock units are considered to be dilutive.

The effect of the Company’s dilutive securities is calculated using the treasury stock method and only those instruments that result in a reduction in net income per common share are included in the calculation. Options to purchase 3.0 million and 2.8 million shares of common stock at weighted average exercise prices of $11.65 and $9.42 were outstanding at June 30, 2018 and 2017, respectively, but were not included in the computation of diluted weighted average common shares outstanding, as the exercise price of the options exceeded the average price of the Company’s common stock during those periods, and therefore are anti-dilutive.

Basic and diluted net income per common share is calculated as follows:


	Three months ended June 30,				Six months ended June 30,
	2018		2017		2018		2017
Net income (in thousands)	$	3,754	$	864	$	9,211	$	5,240
Basic weighted average shares of common stock outstanding		57,315,472		56,839,823		57,218,389		56,818,406
Dilutive effect of share-based awards		998,651		536,115		934,961		926,411
Diluted weighted average common shares outstanding		58,314,123		57,375,938		58,153,350		57,744,817
Net income per share:
Basic	$	0.07	$	0.02	$	0.16	$	0.09
Diluted	$	0.06	$	0.02	$	0.16	$	0.09