We calculate earnings per share in accordance with ASC subtopic 260-10, Earnings per Share, using the two-class method. The two-class method requires that share-based awards with non-forfeitable dividends be classified as participating securities. In calculating basic earnings per share, this method requires net income to be reduced by the amount of dividends declared in the current period for each participating security and by the contractual amount of dividends or other participation payments that are paid or accumulated for the current period. Undistributed earnings for the period are allocated to participating securities based on the contractual participation rights of the security to share in those current earnings assuming all earnings for the period are distributed. Recipients of certain of our restricted stock unit awards have contractual participation rights that are equivalent to those of common stockholders. Therefore, we allocate undistributed earnings to these restricted stock unit participating securities and common stock based on their respective participation percentage.

The two-class method also requires the denominator to include the weighted average number of shares of restricted stock unit participating securities when calculating basic earnings per share. For both the three and six months ended June 30, 2011, there are 0.9 million weighted average restricted stock unit participating securities. For both the three and six months ended June 30, 2010, there are 1.2 million weighted average restricted stock unit participating securities. Diluted earnings per share also include the additional share equivalents from the assumed conversion of stock based awards including options and certain restricted stock units. Conversion of the options is calculated using the treasury stock method, subject to the anti-dilution provisions of ASC subtopic 260-10.

In computing diluted earnings per share for the three and six months ended June 30, 2011, common stock equivalents of 0.2 million shares and 0.2 million shares, respectively, were not included due to their anti-dilutive effect. For the three and six months ended June 30, 2010, all common stock equivalents were excluded due to their anti-dilutive effect.

Computations of common stock basic and diluted earnings per share are presented in the following table:

		Three months ended June 30,				Six months ended June 30,

In thousands, except per share data		2011		2010		2011		2010
Basic earnings per share
Undistributed income		$	14,588	$	21,689	$	26,715	$	2,658
Deduct: Undistributed earnings—Restricted stock unit participating securities			376		738		690		89

Common stockholders' interest in undistributed income		$	14,212	$	20,951	$	26,025	$	2,569

Weighted average common shares—Basic			33,976		33,722		33,971		33,721
Total common stockholders' basic earnings per share		$	0.42	$	0.62	$	0.77	$	0.08

Diluted earnings per share
Common stockholders' interest in undistributed income used in diluted earnings per share		$	14,212	$	20,951	$	26,025	$	2,569

Weighted average common shares—Basic			33,976		33,722		33,971		33,721
	Stock based awards		26		—		21		—

Weighted average common shares—Diluted			34,002		33,722		33,992		33,721

Total common stockholders' diluted earnings per share		$	0.42	$	0.62	$	0.77	$	0.08