Earnings Per Share

3 Months Ended

Mar. 31, 2013

Earnings Per Share

Earnings Per Share

6. Earnings Per Share

Basic income per share is calculated by dividing net income by the weighted average number of common shares outstanding during the period.  Diluted income per share is calculated by dividing net income by the weighted average number of common shares and dilutive common share equivalents outstanding during the period.  Our common share equivalents consist of stock options and restricted stock awards and units.

The following table reconciles the basic to diluted weighted average shares outstanding using the treasury stock method (shares in thousands):

	Three months ended
	March 31,
	2013	2012
Weighted average shares outstanding — basic	87,138	85,864
Dilutive effect of stock options	1,485	2,377
Dilutive effect of restricted stock awards and units	203	335
Weighted average shares outstanding - diluted	88,826	88,576

For the three months ended March 31, 2013 and 2012, 594,318 and 57,804 stock options, respectively, were not included in the diluted earnings per share calculation because the effect would have been anti-dilutive.

For the three months ended March 31, 2013, 64,054 restricted stock units were not included in the diluted earnings per share calculation because the effect would have been anti-dilutive. For the three months ended March 31, 2012, restricted stock units did not have an anti-dilutive effect.