STOCK BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Stock-Based Compensation Expense

The following table provides information regarding the amount and components of stock-based compensation expense, all of which is included in general and administrative expenses in the accompanying Condensed Consolidated Statements of Operations (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Restricted stock units ⁽¹⁾	$	2,673	$	2,157	$	6,778	$	6,348
Stock options	918		1,162		3,103		3,308
New TMM units ⁽²⁾	—		58		—		571
Total stock compensation	$	3,591	$	3,377	$	9,881	$	10,227

⁽¹⁾Includes compensation expense related to time-based RSUs and performance-based RSUs. Outstanding performance-based RSUs reflected in the table above are reported at target level of performance.

⁽²⁾As of December 31, 2017, all new TMM units were vested, and there is no further expense associated with them.

Summary of Activity of Stock Units

The following table summarizes the time-based RSU and performance-based RSU activity for the nine months ended September 30, 2018:



	Shares		Weighted Average Grant Date Fair Value
Balance at December 31, 2017	1,889,559		$	14.84
Granted	574,285		24.06
Vested	(225,106	)	15.31
Forfeited ⁽¹⁾	(367,860	)	16.59
Balance at September 30, 2018	1,870,878		$	17.10

⁽¹⁾Forfeitures on time-based RSUs are a result of termination of employment, while forfeitures on performance-based RSUs are a result of failing to attain certain goals as outlined in our stock based compensation awards or termination of employment.

The shares of Class B Common Stock/New TMM Units held by members of management and members of our Board of Directors as of September 30, 2018 were as follows:



	Class B Shares/New TMM Units		Weighted Average Grant Date Fair Value
Balance at December 31, 2017	883,921		$	5.24
Exchanges ⁽¹⁾	(20,487	)	6.93
Balance at September 30, 2018	863,434		$	5.20

⁽¹⁾Exchanges during the period represent the exchange of a vested New TMM Unit along with the corresponding share of Class B Common Stock for a newly issued share of Class A Common Stock.

Summary of Stock Option Activity

The following table summarizes the stock option activity for the nine months ended September 30, 2018:



	Shares		Weighted Average Exercise Price Per Share
Outstanding at December 31, 2017	2,854,213		$	17.50
Granted	721,762		23.86
Exercised	(118,992	)	15.85
Canceled/Forfeited	(199,742	)	18.60
Outstanding at September 30, 2018	3,257,241		$	18.88
Options exercisable at September 30, 2018	1,535,093		$	18.80