	Three Months Ended						Six Months Ended
	June 30,						June 30,
(in thousands)	2020			2019			2020			2019
Performance unit incentive plan (“PUP”)⁽¹⁾	$	(110	)	$	1,557		$	(2,745	)	$	2,980
Restricted stock		602			783			1,252			1,476
Restricted stock units		365			71			205			161
Share-based compensation (income) expense before income tax		857			2,411			(1,288	)		4,617
Income tax expense (benefit)⁽²⁾		109			(607	)		—			(1,165	)
Share-based compensation (income) expense, net of income tax	$	966		$	1,804		$	(1,288	)	$	3,452

The following table summarizes the activity of the outstanding share-based compensation awards:

	PUP Awards					Restricted Stock					Restricted Stock Units
	Shares			Weighted-Average Grant Date Fair Value		Shares			Weighted-Average Grant Date Fair Value		Shares			Weighted-Average Grant Date Fair Value
Balance at December 31, 2019		214,904		$	52.53		136,123		$	52.66		11,623		$	52.17
Granted		84,898		$	56.15		49,847		$	54.45		3,952		$	50.43
Vested		(67,866	)	$	47.43		(64,429	)	$	49.83		(2,815	)	$	47.45
Forfeited		(18,370	)	$	56.40		(12,865	)	$	56.58		(1,634	)	$	56.59
Balance at June 30, 2020		213,566		$	55.26		108,676		$	54.69		11,126		$	52.10

We grant share-based compensation awards to our officers, directors, and certain key employees pursuant to the 2017 Viad Corp Omnibus Incentive Plan (the “2017 Plan”). The 2017 Plan has a 10-year term and provides for the following types of awards: (a) incentive and non-qualified stock options; (b) restricted stock and restricted stock units; (c) performance units or performance shares; (d) stock appreciation rights; (e) cash-based awards; and (f) certain other stock-based awards. In June 2017, we registered 1,750,000 shares of common stock issuable under the 2017 Plan. As of June 30, 2020, there were 1,514,596 shares available for future grant under the 2017 Plan.

The vesting of PUP award shares is based upon achievement of certain performance-based criteria over a three-year period.

During the six months ended June 30, 2020, we granted PUP awards with a grant date fair value of $4.8 million of which $1.8 million are payable in shares. Liabilities related to PUP awards were $0.3 million as of June 30, 2020 and $5.3 million as of December 31, 2019. In 2020, PUP awards granted in 2017 vested and we paid $2.6 million in cash. No PUP awards were paid in shares in 2020. In 2019, PUP awards granted in 2016 vested and we paid $5.6 million in cash and $3.4 million in shares. In 2019, we withheld 25,771 shares for $1.5 million related to tax withholding requirements on vested PUP awards paid in shares.

As of June 30, 2020, the unamortized cost of outstanding restricted stock awards was $3.2 million, which we expect to recognize over a weighted-average period of approximately 1.5 years. We repurchased 17,881 shares for $1.1 million during the six months ended June 30, 2020 and 24,217 shares for $1.4 million during the six months ended June 30, 2019 related to tax withholding requirements on vested share-based awards.

Aggregate liabilities related to restricted stock units were $0.5 million as of June 30, 2020 and $0.4 million as of December 31, 2019. During the six months ended June 30, 2020, restricted stock units vested and we paid $0.2 million in cash. During the six months ended June 30, 2019, restricted stock units vested and we paid $0.3 million in cash and $0.2 million in shares.

	Shares			Weighted-Average Exercise Price
Options outstanding and exercisable at December 31, 2019		41,143		$	16.62
Exercised		(41,143	)	$	16.62
Options outstanding and exercisable at June 30, 2020		—		$	—