Stock-based Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2018

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,
		2018		2017			2018		2017
Direct operating expense	$	537	$	517		$	1,667	$	1,563
Brokered natural gas and marketing expense		403		389			1,001		1,040
Exploration expense		405		561			1,527		1,596
General and administrative expense		5,607		9,959			38,332		35,156
Termination costs		—		(31	)		—		1,665
Total stock-based compensation	$	6,952	$	11,395		$	42,527	$	41,020

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, 2018:

	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, 2017		833,058		$	31.64		55,202		$	32.26
Granted		1,816,432			16.97		877,191			15.30
Vested		(792,382	)		23.76		(733,634	)		15.99
Forfeited		(191,332	)		21.74		(23,900	)		19.76
Outstanding at September 30, 2018		1,665,776		$	20.53		174,859		$	17.14

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 2018 and 2017:

	Nine Months Ended September 30,
	2018			2017
Risk-free interest rate		2.42	%		1.49	%
Expected annual volatility		48	%		44	%
Grant date fair value per unit	$	18.51		$	26.26

Stock Option and SARs Activities

Information with respect to our SARs activities is summarized below.

	Shares		Weighted Average Exercise Price
Outstanding at December 31, 2017	382,779		$	76.54
Expired/forfeited	(381,675	)		75.97
Outstanding at September 30, 2018	1,104		$	81.74

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 September30,2018:

Number of Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2017	122,921		$	18.66
Units granted (a)	440,938			15.22
Forfeited (b)	(27,061	)		23.03
Outstanding at September 30, 2018	536,798		$	15.61

^(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.

^(b) The first of three tranches of PG-PSUs granted in 2017 are considered forfeited as the performance metric was not met.

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, 2017		1,009,842		$	38.38
Units granted (a)		329,486			18.51
Vested and issued (b)		(73,985	)		56.81
Forfeited		(197,457	)		55.46
Outstanding at September 30, 2018		1,067,886		$	27.81

^(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 73,985 TSR-PSUs awards issued related to the 2015 performance period where the return on our common stock was the 46^th percentile for the February 2015 grant and 36^th percentile for the May 2015 grant. The remaining 2015 awards are considered to be forfeited.