Basic net income per share is calculated by dividing net income by the weighted average number of common shares outstanding for the period. Diluted earnings per share is computed by dividing net income by the weighted average number of shares assuming dilution. Dilutive common shares outstanding is computed using the Treasury Stock Method and reflects the additional shares that would be outstanding if dilutive stock options were exercised and restricted stock units were settled for common shares during the period.

The weighted average number of common shares used to compute basic and diluted net income per share for the quarters ended March 31, 2021 and 2020 were as follows (shares in thousands):

	For the Quarter Ended March 31,
	2021		2020
Basic common shares outstanding		70,149		69,839
Common stock equivalents		1,333		1,875
Diluted common shares outstanding		71,482		71,714

For the quarters ended March 31, 2021 and 2020, certain unexercised stock option awards are excluded from our computations of diluted earnings per share, as these shares were out-of-the-money and their effect would have been anti-dilutive. The anti-dilutive options that were excluded from our computations of diluted earnings per share were 0.5 million and 0.6 million shares for the quarters ended March 31, 2021 and 2020, respectively.