Common Shares

We calculate basic earnings per common share based upon the weighted average number of common shares outstanding. We calculate diluted earnings per share based upon the weighted average number of common shares outstanding plus the dilutive effect of common share equivalents calculated using the treasury stock method. The following is a summary of common shares and common share equivalents outstanding used in the calculations of basic and diluted earnings per share:



	Three Months Ended December 31,		Nine Months Ended December 31,
	2013	2012	2013	2012
Denominator (shares in thousands):
Weighted average common shares outstanding—basic	58,885	58,425	58,972	58,200
Dilutive effect of common share equivalents	800	547	774	492
Weighted average common shares outstanding and common share equivalents—diluted	59,685	58,972	59,746	58,692

Options to purchase the following number of common shares were outstanding but excluded from the computation of diluted earnings per share because the combined exercise prices, unamortized fair values, and assumed tax benefits upon exercise were greater than the average market price for the common shares during the periods, so including these options would be anti-dilutive:



	Three Months Ended December 31,		Nine Months Ended December 31,
	2013	2012	2013	2012
(shares in thousands)
Number of common share options	304	569	336	787