Stock-based Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2019

Allocation of Stock-Based Compensation by Functional Category

The following details the allocation of stock-based compensation to functional expense categories (in thousands):

		Three Months Ended September 30,				Nine Months Ended September 30,
		2019		2018		2019		2018
Direct operating expense	$	319	$	537	$	1,459	$	1,667
Brokered natural gas and marketing expense		522		403		1,523		1,001
Exploration expense		496		405		1,372		1,527
General and administrative expense		8,423		5,607		27,561		38,332
Termination costs		(1)		—		25		—
Total stock-based compensation	$	9,759	$	6,952	$	31,940	$	42,527

Restricted Stock and Restricted Stock Units Outstanding

The following is a summary of the status of our non-vested restricted stock outstanding at September 30, 2019:

	Restricted Stock Equity Awards					Restricted Stock Liability Awards
	Shares			Weighted Average Grant Date Fair Value		Shares			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2018		1,386,088		$	20.04		184,579		$	15.65
Granted		2,792,438			10.59		1,206,480			10.20
Vested		(1,246,420	)		15.73		(733,187	)		10.76
Forfeited		(370,035	)		13.44		—			—
Outstanding at September 30, 2019		2,562,071		$	12.79		657,872		$	11.10

Schedule of Share Based Payment Award Performance Stock Awards Valuation Assumptions

The following assumptions were used to estimate the fair value of PSUs granted during first nine months 2019 and 2018:

	Nine Months Ended September 30,
	2019			2018
Risk-free interest rate		2.4	%		2.4	%
Expected annual volatility		46	%		48	%
Grant date fair value per unit	$	11.34		$	18.51

Stock Option and SARs Activities

Information with respect to our SARs activity is summarized below.

	Shares		Weighted Average Exercise Price
Outstanding at December 31, 2018	1,104		$	81.74
Expired	(1,104	)		81.74
Outstanding at September 30, 2019	—		$	—

Performance-based PG-PSUs and RG-PSUs

Summary of Non-Vested Awards Activities

The following is a summary of our non-vested PG/RG-PSUs awards outstanding at September 30,

Number of Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2018	536,798		$	15.61
Units granted (a)	345,202			10.32
Forfeited	(427	)		15.65
Outstanding at September 30, 2019	881,573		$	11.70

^{(a) Amounts granted reflect the number of performance units granted; however, the actual payout of shares will be between zero and 200% depending on achievement of specifically identified performance targets.}

Performance Based TSR - PSUs

Summary of Non-Vested Awards Activities

The following is a summary of our non-vested TSR – PSUs award activities:

	Number of Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2018		1,067,886		$	27.81
Units granted (a)		314,152			11.34
Vested and issued (b)		(12,283	)		30.47
Forfeited		(376,303	)		37.25
Outstanding at September 30, 2019		993,452		$	19.00

^(a) These amounts reflect the number of performance units granted. The actual payout of shares may be between zero and 200% of the performance units granted depending on the total shareholder return ranking compared to our peer companies at the vesting date.

^(b) Includes 12,283 TSR-PSUs awards issued related to the 2016 performance period where the return on our common stock was in the 20^th percentile for the February 2016 grant. The remaining February 2016 awards are considered to be forfeited. The May 2016 awards were  100% forfeited as the performance was not achieved.