Earnings Per Share

The following table sets forth the computation of basic and diluted earnings (loss) per share (EPS):



	Three Months Ended March 31,
	2018			2017
	(in thousands, except per share data)
Net income (loss) available to common shareholders	$	(145,666	)	$	15,845

Weighted average common shares outstanding - Basic	38,945			38,474
Dilutive effect of stock-based awards	—			741
Weighted average common shares outstanding - Diluted	38,945			39,215
Earnings (loss) per common share - Basic	$	(3.74	)	$	0.41
Earnings (loss) per common share - Diluted	$	(3.74	)	$	0.40

Stock-based Awards

For stock-based awards, the dilutive effect is calculated using the treasury stock method. Under this method, the dilutive effect is computed as if the awards were exercised at the beginning of the period (or at time of issuance, if later) and assumes the related proceeds were used to repurchase common stock at the average market price during the period. Related proceeds include the amount the employee must pay upon exercise and the future compensation cost associated with the stock award. Approximately 1.0 million and 0.2 million stock-based awards were excluded from the calculation of diluted EPS for the three months ended March 31, 2018 and 2017 because they were anti-dilutive. As a result of our net loss for the three months ended March 31, 2018, there was no dilutive effect to weighted average common shares outstanding.