Earnings Per Share (Notes)

3 Months Ended

Mar. 31, 2021

Basic earnings per share are computed based on the weighted average number of common shares outstanding during the period. Diluted earnings per share are computed using the weighted average number of common shares outstanding and the effect of dilutive potential common shares outstanding during the period using the treasury stock method. Potential common shares consist of: i) employee stock purchase plan shares; and ii) contingently issuable time-based and performance-based restricted stock units, along with associated dividend equivalent rights. Unvested performance-based restricted stock units and associated dividend equivalent rights are included in dilutive potential common shares only after the performance criteria have been met.

For the three months ended March 31, 2021, unvested performance-based restricted stock units and related dividend equivalent rights of 373 thousand shares were excluded from the dilutive calculation because the performance goals had not been met, with 301 thousand shares excluded for the three months ended March 31, 2020.

Net income (loss) is the same for both the basic and diluted earnings per share computations. The denominators of the basic and diluted earnings per share computations are as follows (in thousands):


	Three Months Ended March 31,
		2021	2020
Weighted-average common shares outstanding—basic		89,556	89,429
Dilutive effect of potential common shares		147	150
Weighted-average common shares outstanding—diluted		89,703	89,579