Equity-Based Compensation Plans

We reserved 5.0 million shares for issuance to key management personnel and directors under the 2011 amended and restated long-term incentive and equity award plan. As of December 31, 2018, 1.5 million shares remain available for future issuance under this plan. The plan permits the issuance of restricted stock and stock units, as well as options, stock appreciation rights, and performance stock and performance stock unit awards. Awards under the plan can be satisfied in cash or shares at the discretion of the Board of Directors. According to the plan provisions, the stock units provide the holders the right to receive one share of our Common Stock upon vesting (and distribution) of one stock unit. The plan requires the exercise price of any option granted to equal the closing market price of our Common Stock on the date of grant.

Performance Based Awards

In 2015, the Company granted performance stock unit awards to employees under its 2015 long-term incentive plan. The awards provide a target number of stock units that vested equally over three years.

A summary of performance-based unvested stock unit activity is as follows:



(stock units in thousands)	Units (in thousands)		Weighted Average Grant-Date Fair Value
Unvested at December 31, 2015	421		$	18.09
Vested	(140	)	17.90
Forfeited	(20	)	16.83
Unvested at December 31, 2016	261		$	17.98
Vested	(141	)	17.90
Forfeited	(6	)	18.23
Unvested at December 31, 2017	114		$	18.06
Vested	(114	)	18.06
Forfeited	—		—
Unvested at December 31, 2018	—		$	—

The Company expenses the grant date fair value of the awards earned in the performance period over the respective service periods. For the years ended December 31, 2018 and 2017, the Company recognized compensation expense of $0.1 million and $0.9 million, respectively. These awards were fully expensed by February 2018.

The fair value of shares vested and distributed during the year ended December 31, 2018 was $2.1 million.

In March 2016, the Company granted performance-based stock unit awards to employees that were to be settled in cash upon the achievement of specified performance criteria for 2016. No awards were earned as the 2016 performance criteria were not achieved.

Restricted Stock

A summary of the activity of our unvested restricted stock and stock unit awards are presented in the following table:



	Shares/units (in thousands)		Weighted Average Grant-Date Fair Value
Unvested at December 31, 2015	767		$	14.34
Granted	730		8.76
Vested and distributed	(269	)	12.90
Forfeited	(53	)	11.60
Unvested at December 31, 2016	1,175		$	11.30
Granted	496		12.43
Vested and distributed	(306	)	11.91
Forfeited	(58	)	12.28
Unvested at December 31, 2017	1,307		$	11.55
Granted	730		9.35
Vested and distributed	(457	)	10.91
Forfeited	(164	)	11.31
Unvested at December 31, 2018	1,416		$	10.65

All of the members of the Board of Directors have deferred receipt of the Common Stock underlying some or all of the restricted stock units they have been awarded until each such director ceases to serve on the Board or, under certain circumstances, upon a change of control. Thus, while some of these restricted stock units have vested, the directors have not yet received the underlying Common Stock. For the years ended December 31, 2018, 2017, and 2016, the total number of restricted stock units that are vested but for which the underlying Common Stock has not been distributed was 660,000, 528,000, and 410,000, respectively; these shares are shown as unvested in the above table.

The intrinsic value of unvested shares as of December 31, 2018 was $4.5 million. The Company records expense on a straight-line basis over the vesting term. For the years ended December 31, 2018, 2017 and 2016, the Company recorded compensation expense for restricted stock awards of $6.2 million, $5.6 million, and $5.0 million, respectively. Unrecognized compensation expense related to restricted stock awards of $4.0 million at December 31, 2018 is expected to be recognized over a weighted-average period of 0.9 years.

The vesting provisions for the restricted stock and stock unit awards and the related number of shares granted during the year ended December 31 are as follows:



	Shares/units (in thousands)
Vesting Terms	2018	2017	2016
25% per year for four years	—	—	8
100% immediately	132	106	123
33.3% per year for three years	452	85	599
100% on February 14, 2020	—	305	—
100% on July 31, 2018	146	—	—
Total restricted stock and stock units granted	730	496	730

The fair value of nonvested shares is determined based on the closing trading price of our shares on the grant date. The fair value of shares vested and distributed during the years ended December 31, 2018, 2017 and 2016 was $5.0 million, $3.6 million, and $3.5 million, respectively.

The outstanding awards under our stock compensation plans are considered participating securities in our earnings per share calculation.