At June 30, 2021, approximately 1.0 million shares are available for future use under our long-term incentive plans.

Share-based compensation activity during the six months ended June 30, 2021 included the following:

(Shares in thousands)	Granted		Vested		Forfeited
Performance Share Awards (PSAs)		88,128		—		1,450
Restricted Stock Units (RSUs)		46,997		23,599		1,484

Approximately 0.1 million shares of common stock were issued during the six months ended June 30, 2021 as a result of PSA and RSU vesting during 2020 and 2021.

The following table details equity-based compensation expense and the related income tax benefit:

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2021		2020		2021		2020
Equity-based compensation expense:
Performance share awards	$	1,372	$	1,243	$	2,596	$	2,401
Restricted stock units		727		718		1,392		1,426
Deferred compensation stock equivalent units expense		41		19		82		38
Total equity-based compensation expense	$	2,140	$	1,980	$	4,070	$	3,865

Total tax benefit recognized for equity-based expense	$	107	$	93	$	196	$	176

The weighted average grant date fair value of PSAs granted in 2021 was $69.72 per share. PSAs granted under the stock incentive plans have a three-year performance period and shares are issued at the end of the period if the performance measures are met. The number of shares actually issued, as a percentage of the amount subject to the PSA, could range from 0% to 200%. PSAs granted under the stock incentive plans do not have voting rights unless and until shares are issued upon settlement. If shares are issued at the end of the performance measurement period, the recipients will receive dividend equivalents in the form of additional shares at the time of payment equal to the dividends that would have been paid on the shares earned had the recipients owned the shares during the three-year period. Therefore, the shares are not considered participating securities.

The following table presents the key inputs used in the Monte Carlo simulation to calculate the fair value of the performance share awards granted in 2021:

Stock price as of valuation date	$	53.53
Risk-free rate		0.18	%
Expected volatility		45.56	%
Expected dividend yield¹		—
Expected term (years)		3.00

The weighted average fair value of all RSUs granted during the six months ended June 30, 2021 was $55.67 per share. The fair value of RSUs granted equaled our common share price on the date of grant factoring in any required post-vesting holding periods. The terms of the awards state that the RSUs will vest in a given time period of one to three years. The vesting provisions for RSUs granted in 2021 were consistent with prior year grants.