The following table reconciles the number of shares used in calculating basic and diluted earnings per share:

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2021		2020		2021		2020
Basic weighted-average shares outstanding		67,316		67,176		67,265		67,321
Incremental shares due to:
Performance shares		355		153		343		—
Restricted stock units		61		30		56		—
Diluted weighted-average shares outstanding		67,732		67,359		67,664		67,321

For stock-based awards, the dilutive effect is calculated using the treasury stock method. Under this method, the dilutive effect is computed as if the awards were exercised at the beginning of the period (or at time of issuance, if later) and assumes the related proceeds were used to repurchase common stock at the average market price during the period. Related proceeds include future compensation cost associated with the stock award.

For the three and six months ended June 30, 2021, there were approximately 75,000 and 78,000 stock-based awards, respectively, that were excluded from the calculation of diluted earnings per share as they were anti-dilutive. For the three and six months ended June 30, 2020, there were approximately 39,000 and 490,000 stock-based awards, respectively, that were excluded from the calculation of diluted earnings per share because they were anti-dilutive. Anti-dilutive stock-based awards could be dilutive in future periods.

On August 30, 2018, our board of directors authorized management to repurchase up to $100.0 million of common stock with no time limit set for the repurchase (the Repurchase Program). Shares under the Repurchase Program may be repurchased in open market transactions, including pursuant to a trading plan adopted in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934 (the Trading Plan). The timing, manner, price and amount of repurchases will be determined according to, and subject to, the terms of the Trading Plan, and, subject to the terms of the Trading Plan, the Repurchase Program may be suspended, terminated or modified at any time for any reason.

We did not repurchase any shares during the six months ended June 30, 2021. During the three and six months ended June 30, 2020, we repurchased 88,933 and 489,850 shares of common stock (at a total consideration of $3.0 million and $15.4 million), respectively under the Repurchase Program, all of which were made in open-market transactions. At June 30, 2021, we had remaining authorization of $59.5 million for future stock repurchases under the Repurchase Program.

We record share repurchases upon trade date as opposed to the settlement date when cash is disbursed. We record a liability to account for repurchases that have not been cash settled. We retire shares upon repurchase. Any excess repurchase price over par is recorded in accumulated deficit.