Net Income Per Common Share

Basic net income per common share is computed by dividing net income by the weighted average number of common shares outstanding during the period. Weighted average common shares outstanding for the basic net income per common share calculation includes certain vested restricted stock units (RSUs) and performance stock units (PSUs) as there are no conditions under which those shares will not be issued. Diluted net income per common share is computed by dividing net income by the combination of other potentially dilutive weighted average common shares and the weighted average number of common shares outstanding during the period. Other potentially dilutive weighted average common shares include the dilutive effect of stock options, RSUs, and PSUs for each period using the treasury stock method. Under the treasury stock method, the exercise price of a share and the amount of compensation expense, if any, for future service that has not yet been recognized are assumed to be used to repurchase shares in the current period.

The following table sets forth the computation of basic and diluted net income per common share:



	Three Months Ended September 30				Nine Months Ended September 30
	2017		2016		2017		2016
	(thousands, except per-share data)
Net income	$	31,661	$	9,981	$	63,835	$	34,159
Weighted average common shares outstanding during the period (for basic calculation)	38,660		38,814		38,601		38,827
Dilutive effect of other potential common shares	479		306		361		123
Weighted average common shares and potential common shares (for diluted calculation)	39,139		39,120		38,962		38,950

Net income per common share - Basic	$	0.82	$	0.26	$	1.65	$	0.88
Net income per common share - Diluted	$	0.81	$	0.26	$	1.64	$	0.88

The computation of the dilutive effect of other potential common shares excludes stock awards representing no shares and 0.2 million shares of common stock, respectively, in the three months ended September 30, 2017 and 2016, and 0.2 million shares of common stock in both the nine months ended September 30, 2017 and 2016. Under the treasury stock method, the inclusion of these stock awards would have been antidilutive.