Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2013

Fair Value Hierarchy Table for Assets and Liabilities Measured at Fair Value

		Fair Value Measurements at June30, 2013 using:
		QuotedPrices in Active Markets for IdenticalAssets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Carrying Valueasof June30, 2013
Trading securities held in the deferred compensation plans		$	62,036	$	—	$	—	$	62,036
Derivatives	–swaps		—		41,156		—		41,156
	–collars		—		86,363		—		86,363

		Fair Value Measurements at December31, 2012 using:
		Quoted Prices in Active Markets for IdenticalAssets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Carrying Value as of December31, 2012
Trading securities held in the deferred compensation plans		$	57,776	$	—	$	—	$	57,776
Derivatives	–swaps		—		23,326		—		23,326
	–collars		—		121,014		—		121,014
	–basis swaps		—		993		—		993

Value of Assets Measured at Fair Value on Non Recurring Basis

	Fair Value			Impairment
Surface property		$	5,550		$	741

Carrying Amounts and Fair Values of Financial Instruments

The following table presents the carrying amounts and the fair values of our financial instruments as of June 30, 2013 and December31, 2012 (in thousands):

	June30,2013								December31,2012
	Carrying Value				Fair Value					Carrying Value				Fair Value
Assets:
Commodity swaps and collars	$	127,519		$		127,519		$			153,267		$		153,267
Marketable securities(a)		62,036				62,036					57,776				57,776
(Liabilities):
Commodity swaps and collars		—				—					(7,934	)			(7,934	)
Bank credit facility(b)		(309,000	)			(309,000	)				(739,000	)			(739,000	)
Deferred compensation plan(c)		(207,906	)			(207,906	)				(187,604	)			(187,604	)
7.25% senior subordinated notes due 2018(b)		—				—					(250,000	)			(262,500	)
8.00% senior subordinated notes due 2019(b)		(289,835	)			(319,500	)				(289,185	)			(332,250	)
6.75% senior subordinated notes due 2020(b)		(500,000	)			(536,250	)				(500,000	)			(542,500	)
5.75% senior subordinated notes due 2021(b)		(500,000	)			(515,000	)				(500,000	)			(535,000	)
5.00% senior subordinated notes due 2022(b)		(600,000	)			(586,500	)				(600,000	)			(627,000	)
5.00% senior subordinated notes due 2023(b)		(750,000	)			(733,125	)				—				—

(a)Marketable securities, which are held in our deferred compensation plans, are actively traded on major exchanges. Refer to Note 13 for additional information.

(b)The book value of our bank debt approximates fair value because of its floating rate structure. The fair value of our senior subordinated notes is based on end of period market quotes which are Level 2 market values. Refer to Note 8 for additional information.

(c)The fair value of our deferred compensation plan is updated on the closing price on the balance sheet date.