Stock-based Compensation Plans (Tables)

6 Months Ended

Jun. 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 June 30,					Six Months Ended June 30,
		2018		2017			2018 (1)		2017
Direct operating expense	$	539	$	522		$	1,130	$	1,046
Brokered natural gas and marketing expense		313		388			598		651
Exploration expense		371		528			1,122		1,035
General and administrative expense		8,814		14,279			32,725		25,197
Termination costs		—		(46	)		—		1,696
Total stock-based compensation	$	10,037	$	15,671		$	35,575	$	29,625

⁽¹⁾ Includes $18.2 million accelerated vesting of equity grants.

Restricted Stock and Restricted Stock Units Outstanding

The following is a summary of the status of our non-vested restricted stock outstanding at June 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		1,785,446			17.00		806,129			15.25
Vested		(516,493	)		24.18		(685,966	)		15.88
Forfeited		(128,447	)		22.09		(21,900	)		17.63
Outstanding at June 30, 2018		1,973,564		$	20.97		153,465		$	18.22

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 six months 2018 and 2017:

	Six Months Ended June 30,
	2018			2017
Risk-free interest rate		2.42	%		1.49	%
Expected annual volatility		47	%		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 June 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 June30,2018:

Number of Units			Weighted Average Grant Date Fair Value of Range Stock
Outstanding at December 31, 2017	122,921		$	18.66
Units granted (a)	440,938			15.22
Forfeited (b)	(23,668	)		24.15
Outstanding at June 30, 2018	540,191		$	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)		(76,149	)		56.81
Forfeited		(191,398	)		56.10
Outstanding at June 30, 2018		1,071,781		$	27.80

^(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 76,149 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.