In May 2016, our stockholders approved and our board of directors adopted an amended and restated Long Term Incentive Plan (the “Incentive Plan”), which provides for the grants of awards to our directors, officers, employees, and consultants. The Incentive Plan authorizes the grant of restricted or unrestricted shares of our common stock, performance share units (“PSUs”), non-qualified and incentive stock options, restricted stock units (“RSUs”), stock appreciation rights (“SARs”), dividend equivalents and other stock- or cash-based awards. In conjunction with the amendment, the number of shares of common stock issuable under the Incentive Plan was increased to 4,300,000 shares and the term of the Incentive Plan was extended to May 12, 2026.

Under the Incentive Plan, we have granted restricted shares, RSUs, SARs, and PSUs. For the years ended December 31, 2020, 2019 and 2018 we recognized $5,635, $3,166 and $2,524 of stock compensation expense, respectively. In 2020, our PSU and RSU award agreements were revised to provide for accelerated vesting upon retirement, as defined in the award agreements. Due to this revision, the stock compensation expense associated with any such award granted to a retirement eligible employee is recognized in full on the date of grant. During the year ended December 31, 2020, $1,667 of stock compensation was recognized with respect to awards granted to retirement eligible employees.

The restricted shares and RSUs granted under the Incentive Plan generally vest over a two, three, or four year period. In addition, we have granted unrestricted shares to our directors. These awards generally vested immediately. A summary of restricted common share award and RSU activity is presented below.

	2020					2019					2018
	Number of Shares			Weighted Average Grant Date Fair Value Per Share		Number of Shares			Weighted Average Grant Date Fair Value Per Share		Number of Shares			Weighted Average Grant Date Fair Value Per Share
Balance, January 1,		326,541		$	9.54		303,819		$	8.22		295,847		$	7.84
Granted		282,735			12.85		213,744			10.39		233,706			8.64
Vested		(164,026	)		9.32		(174,367	)		9.27		(175,555	)		7.99
Forfeited		(38,401	)		12.20		(16,655	)		9.75		(50,179	)		8.45
Balance, December 31, (1)		406,849		$	11.68		326,541		$	9.54		303,819		$	8.22

Subsequent to December 31, 2020, 86,591 restricted stock awards and RSUs valued at a weighted-average price of $14.17, or $1,227 in the aggregate were awarded to employees. These awards vest over a two or three-year period.

As of December 31, 2020, the unearned compensation cost relating to unvested restricted common share awards and RSUs was $2,437, which will be recognized over a weighted-average period of 1.8 years. The estimated fair value of restricted common share awards, and RSUs, vested during 2020, 2019, and 2018 was $2,076, $1,836, and $1,539, respectively.

The PSUs granted under the Incentive Plan have a three-year performance period and are generally based on (1) market performance as measured by total stockholder return for 70% of the award and (2) a subjective performance condition tied to achievement of specified individual criteria for 30% of the award. The PSUs vest 50% upon the Compensation Committee’s determination as to the satisfaction of the performance criteria (which shall be within two months of the last day of the performance period) and 50% on the first anniversary of the last day of the performance period, subject to continued service through such dates. A summary of PSU activity is presented below.

	2020					2019				2018
	Number of Shares			Weighted Average Grant Date Fair Value Per Share		Number of Shares		Weighted Average Grant Date Fair Value Per Share		Number of Shares		Weighted Average Grant Date Fair Value Per Share
Balance, January 1,		717,677		$	7.52		453,748	$	7.04		150,980	$	7.12
Granted (1)		202,145			11.77		263,929		8.35		302,768		7.00
Change in awards based on performance (2)		75,488		$	7.12		—		0.00		—		0.00
Vested		(113,234	)		7.12		—		0.00		—		0.00
Balance, December 31,		882,076		$	8.21		717,677	$	7.52		453,748	$	7.04

Our assumptions used in computing the fair value of the PSUs at the dates of their respective awards, using the Monte Carlo method, were as follows:

The Company estimates future expenses associated with PSUs outstanding at December 31, 2020 to be $2,131, which will be recognized over a weighted-average period of 2.3 years. The estimated fair value of PSUs vested during 2020, 2019, and 2018 was $1,862, $0, and $0.

	2020					2019					2018
	SARs			Weighted Average Exercise Price		SARs			Weighted Average Exercise Price		SARs			Weighted Average Exercise Price
Outstanding, January 1,		9,000		$	9.35		195,000		$	9.35		250,000		$	9.28
Granted		—			—		—			—		—			—
Expired		(9,000	)		9.35		—			—		—			—
Exercised		—			—		(186,000	)		9.35		(55,000	)		9.02
Forfeited		—			—		—			—		—			—
Outstanding, December 31,		—		$	9.35		9,000		$	9.35		195,000		$	9.35
SARs exercisable at December 31,		—					9,000					195,000