Stock-Based Compensation Plans (Tables)

6 Months Ended

Jun. 30, 2013

Allocation of Stock-Based Compensation by Functional Category

	Three Months Ended June 30,				Six Months Ended June 30,
	2013		2012		2013		2012
Operating expense	$	696	$	692	$	1,357	$	1,049
Brokered natural gas and marketing expense		530		408		779		861
Exploration expense		960		994		2,030		1,922
General and administrative expense		13,263		12,540		23,569		20,698
Total	$	15,449	$	14,634	$	27,735	$	24,530

Stock Option and SARs Activities

	Shares		Weighted Average ExercisePrice
Outstanding at December31, 2012	3,433,362		$	52.52
Granted	470,617			75.31
Exercised	(1,115,480	)		54.01
Expired/forfeited	(42,411	)		53.81
Outstanding at June 30, 2013	2,746,088		$	55.83

Weighted Average Grant Date Fair Value of SARs

	SixMonths Ended June30, 2013
Weighted average exercise price per share	$	75.31
Expected annual dividends per share		0.21	%
Expected life in years		3.7
Expected volatility		35	%
Risk-free interest rate		0.6	%
Weighted average grant date fair value per share	$	20.19

Restricted Stock and Restricted Stock Units Outstanding

A summary of the status of our non-vested restricted stock outstanding at June 30, 2013 is summarized below:

	Equity Awards					Liability Awards
	Shares			Weighted AverageGrant DateFairValue		Shares				Weighted AverageGrant DateFairValue
Outstanding at December 31, 2012		349,156		$	59.08		423,478		$		58.91
Granted		388,653			71.05		424,431				75.53
Vested		(153,439	)		61.97		(180,503	)			60.57
Forfeited		(27,914	)		65.02		(21,620	)			57.21
Outstanding at June 30, 2013		556,456		$	66.35		645,786		$		69.43