Range Resources (RRC) 10-Q 30 Oct 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 27, 2013
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	30-Sep-13
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q3
Trading Symbol	RRC
Entity Registrant Name	RANGE RESOURCES CORP
Entity Central Index Key	315852
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		163,421,596

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$255	$252
Accounts receivable, less allowance for doubtful accounts of $2,496 and $2,374	151,407	167,495
Unrealized derivatives	55,993	137,552
Deferred tax asset	2,179
Inventory and other	12,898	22,315
Total current assets	222,732	327,614
Unrealized derivatives	18,074	15,715
Equity method investments	127,236	132,449
Natural gas and oil properties, successful efforts method	8,667,682	8,111,775
Accumulated depletion and depreciation	-2,160,378	-2,015,591
Natural gas and oil properties, successful efforts method, net	6,507,304	6,096,184
Transportation and field assets	117,566	117,717
Accumulated depreciation and amortization	-82,652	-76,150
Transportation and field assets, net	34,914	41,567
Other assets	120,370	115,206
Total assets	7,030,630	6,728,735
Current liabilities:
Accounts payable	251,635	234,651
Asset retirement obligations	2,366	2,470
Accrued liabilities	159,697	139,379
Deferred tax liability		37,924
Accrued interest	31,914	36,248
Unrealized derivatives	7,971	4,471
Total current liabilities	453,583	455,143
Bank debt	427,000	739,000
Subordinated notes	2,640,170	2,139,185
Deferred tax liability	759,556	698,302
Unrealized derivatives	103	3,463
Deferred compensation liability	207,404	187,604
Asset retirement obligations and other liabilities	151,813	148,646
Total liabilities	4,639,629	4,371,343
Commitments and contingencies
Stockholders’ Equity
Preferred stock, $1 par, 10,000,000 shares authorized, none issued and outstanding
Common stock, $0.01 par, 475,000,000 shares authorized, 163,418,445 issued at September 30, 2013 and 162,641,896 issued at December 31, 2012	1,634	1,626
Common stock held in treasury, 101,301 shares at September 30, 2013 and 127,798 shares at December 31, 2012	-3,751	-4,760
Additional paid-in capital	1,944,437	1,915,627
Retained earnings	428,948	360,990
Accumulated other comprehensive income	19,733	83,909
Total stockholders’ equity	2,391,001	2,357,392
Total liabilities and stockholders’ equity	$7,030,630	$6,728,735

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Allowance for doubtful accounts on accounts receivable	$2,496	$2,374
Preferred stock, par value	$1	$1
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued
Preferred stock, shares outstanding
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	475,000,000	475,000,000
Common stock, shares issued	163,418,445	162,641,896
Common stock held in treasury, shares	101,301	127,798

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues and other income:
Natural gas, NGLs and oil sales	$431,214	$337,040	$1,267,131	$953,006
Derivative fair value (loss) income	-40,355	-40,728	-2,470	47,008
Gain (loss) on the sale of assets	6,008	949	89,129	-12,704
Brokered natural gas, marketing and other	45,171	2,519	80,843	12,356
Total revenues and other income	442,038	299,780	1,434,633	999,666
Costs and expenses:
Direct operating	30,907	29,628	93,731	85,691
Transportation, gathering and compression	60,958	51,600	189,422	137,164
Production and ad valorem taxes	11,454	8,819	33,950	57,239
Brokered natural gas and marketing	51,117	4,887	90,094	15,440
Exploration	20,496	14,752	50,344	51,785
Abandonment and impairment of unproved properties	11,692	40,118	46,066	104,048
General and administrative	44,919	44,497	230,964	127,231
Deferred compensation plan	-2,225	20,052	33,257	21,555
Interest expense	44,321	43,997	131,602	124,090
Loss on early extinguishment of debt			12,280
Depletion, depreciation and amortization	130,343	123,059	365,439	332,012
Impairment of proved properties and other assets	7,012	1,281	7,753	1,281
Total costs and expenses	410,994	382,690	1,284,902	1,057,536
Income (loss) from operations before income taxes	31,044	-82,910	149,731	-57,870
Income tax expense (benefit)
Current
Deferred	11,866	-29,074	62,180	-17,910
Total income tax expense	11,866	-29,074	62,180	-17,910
Net income (loss)	$19,178	($53,836)	$87,551	($39,960)
Net income (loss) per common share:
Basic	$0.12	($0.34)	$0.54	($0.25)
Diluted	$0.12	($0.34)	$0.53	($0.25)
Dividends paid per common share	$0.04	$0.04	$0.12	$0.12
Weighted average common shares outstanding:
Basic	160,500	159,563	160,398	159,297
Diluted	161,374	159,563	161,321	159,297

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Net income (loss)	$19,178		($53,836)		$87,551		($39,960)
Other comprehensive income:
Realized loss (gain) on hedge derivative contract settlements reclassified into natural gas, NGLs and oil sales from other comprehensive income, net of taxes			-37,495	[1]	-14,840	[1]	-120,871	[1]
De-designated hedges reclassified into natural gas, NGLs and oil sales, net of taxes	-16,717	[2]			-42,758	[2]
De-designated hedges reclassified to derivative fair value income, net of taxes	-438	[3]			-2,376	[3]
Change in unrealized deferred hedging (losses) gains, net of taxes			-52,246	[4]	-4,203	[4]	31,541	[4]
Total comprehensive income (loss)	$2,023		($143,577)		$23,374		($129,290)
[1]	Amounts are net of income tax expense of $23,972 for the three months ended September 30, 2012 and $9,488 and $76,806 for the nine months ended September 30, 2013 and 2012.
[2]	Amounts are net of income tax expense of $10,688 for the three months ended September 30, 2013 and $27,337 for the nine months ended September 30, 2013.
[3]	Amounts relate to transactions not probable of occurring and are presented net of income tax expense of $279 for the three months ended September 30, 2013 and $1,518 for the nine months ended September 30, 2013.
[4]	Amounts are net of income tax expense of $33,403 for the three months ended September 30, 2012 and income tax benefit of $21,780 for the nine months ended September 30, 2012. Amounts are net of income tax expense of $2,687 for the nine months ended September 30, 2013.

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Realized loss (gain) on hedge derivative contract settlements reclassified into natural gas, NGLs and oil sales from other comprehensive income, tax portion		$23,972	$9,488	$76,806
De-designated hedges reclassified into natural gas, NGLs and oil sales, tax portion	10,688		27,337
De-designated hedges reclassified to derivative fair value income, tax portion	279		1,518
Change in unrealized deferred hedging gains, tax effect		$33,403	$2,687	($21,780)

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating activities:
Net income (loss)	$87,551	($39,960)
Adjustments to reconcile net income (loss) to net cash provided from operating activities:
(Gain) loss from equity method investments, net of distributions	-1,174	2,252
Deferred income tax expense (benefit)	62,180	-17,910
Depletion, depreciation and amortization and impairment	373,192	333,293
Exploration dry hole costs	3,904	832
Mark-to-market on natural gas, NGLs and oil derivatives not designated as hedges	-28,350	-30,076
Abandonment and impairment of unproved properties	46,066	104,048
Unrealized derivative loss	2,485	5,061
Allowance for bad debt	250
Amortization of deferred financing costs, loss on extinguishment of debt and other	19,735	5,970
Deferred and stock-based compensation	74,187	58,573
(Gain) loss on the sale of assets	-89,129	12,704
Changes in working capital:
Accounts receivable	-6,506	-9,479
Inventory and other	3,259	-5,394
Accounts payable	-29,234	11,074
Accrued liabilities and other	-15,550	30,135
Net cash provided from operating activities	502,866	461,123
Investing activities:
Additions to natural gas and oil properties	-907,813	-1,151,167
Additions to field service assets	-4,326	-3,056
Acreage purchases	-70,187	-175,041
Equity method investments	3,799
Proceeds from disposal of assets	311,748	32,082
Purchases of marketable securities held by the deferred compensation plan	-23,729	-33,997
Proceeds from the sales of marketable securities held by the deferred compensation plan	19,375	21,485
Net cash used in investing activities	-671,133	-1,309,694
Financing activities:
Borrowing on credit facilities	1,310,000	1,139,000
Repayment on credit facilities	-1,622,000	-865,000
Issuance of subordinated notes	750,000	600,000
Repayment of subordinated notes	-259,063
Dividends paid	-19,593	-19,475
Debt issuance costs	-12,448	-12,606
Issuance of common stock	343	2,073
Change in cash overdrafts	4,704	-15,750
Proceeds from the sales of common stock held by the deferred compensation plan	16,327	20,388
Net cash provided from financing activities	168,270	848,630
Increase in cash and cash equivalents	3	59
Cash and cash equivalents at beginning of period	252	92
Cash and cash equivalents at end of period	$255	$151

Summary_of_Organization_and_Na

Summary of Organization and Nature of Business	9 Months Ended
	Sep. 30, 2013
Summary of Organization and Nature of Business	(1) SUMMARY OF ORGANIZATION AND NATURE OF BUSINESS
	Range Resources Corporation (“Range,” “we,” “us,” or “our”) is a Fort Worth, Texas-based independent natural gas, natural gas liquids (“NGLs”) and oil company primarily engaged in the exploration, development and acquisition of natural gas and oil properties in the Appalachian and Southwestern regions of the United States. Our objective is to build stockholder value through consistent growth in reserves and production on a cost-efficient basis. Range is a Delaware corporation with our common stock listed and traded on the New York Stock Exchange under the symbol “RRC.”

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Basis of Presentation	(2) BASIS OF PRESENTATION
	Presentation
	These interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Range Resources Corporation 2012 Annual Report on Form 10-K filed on February 27, 2013. The results of operations for the third quarter and the nine months ended September 30, 2013 are not necessarily indicative of the results to be expected for the full year. These consolidated financial statements are unaudited but, in the opinion of management, reflect all adjustments necessary for fair presentation of the results for the periods presented. All adjustments are of a normal recurring nature unless otherwise disclosed. These consolidated financial statements, including selected notes, have been prepared in accordance with the applicable rules of the Securities and Exchange Commission (the “SEC”) and do not include all of the information and disclosures required by accounting principles generally accepted in the United States of America (“U.S. GAAP”) for complete financial statements. Certain reclassifications have been made to prior years reported amounts in order to conform with the current year presentation. These reclassifications include gas purchases and other marketing costs which were previously reported in other income and are currently reported as a separate operating expense. These reclassifications have no impact on previously reported net income.
	Impact Fee
	In first quarter 2012, the Pennsylvania legislature passed an “impact fee” on unconventional natural gas and oil production. The impact fee is a per well annual fee imposed for a period of fifteen years on all unconventional wells drilled in Pennsylvania. The fee is based on the average annual price of natural gas and the Consumer Price Index. The annual fee per well declines each year over the fifteen-year time period as long as the well is producing. In first nine months 2012, we recorded a retroactive impact fee of $24.7 million for wells drilled during 2011 and prior. This expense is reflected in our statements of operations as production and ad valorem taxes.
	De-designation of Commodity Derivative Contracts
	Effective March 1, 2013, we elected to discontinue hedge accounting prospectively. After March 1, 2013, both realized and unrealized gains and losses will be recognized in earnings in derivative fair value income (loss) immediately each quarter as derivative contracts are settled and marked to market. For third quarter 2013, unrealized gains of $3.1 million and for the nine months ended September 30, 2013, unrealized gains of $25.5 million were included in our statements of operations in derivative fair value income (loss) that, prior to March 1, 2013, would have been deferred in accumulated other comprehensive income (“AOCI”) if we had continued using hedge accounting. Refer to Note 11 for additional information.

New_Accounting_Standards

New Accounting Standards	9 Months Ended
	Sep. 30, 2013
New Accounting Standards	(3) NEW ACCOUNTING STANDARDS
	Recently Adopted
	In December 2011, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2011-11, “Disclosures about Offsetting Assets and Liabilities,” requiring additional disclosures about offsetting and related arrangements. ASU 2011-11 is effective retrospectively for annual reporting periods beginning on or after January 1, 2013. Also, in January 2013, the FASB issued ASU No. 2013-01, “Balance Sheet (Topic 210):  Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities.” ASU 2013-01 revised and clarified the disclosures required by ASU No. 2011-11. We adopted these new requirements in first quarter 2013 and they did not have a material effect on our consolidated financial statements.
	In February 2013, the FASB issued ASU No. 2013-02, “Comprehensive Income (Topic 220): Reporting of Amounts Reclassified out of Accumulated Other Comprehensive Income.” ASU 2013-02 requires information to be disclosed about the amounts reclassified out of AOCI by component. We adopted this new requirement in first quarter 2013 and it did not have a material effect on our consolidated financial statements.

Dispositions

Dispositions	9 Months Ended
	Sep. 30, 2013
Dispositions	(4) DISPOSITIONS
	2013 Dispositions
	In September 2013, we sold our equity method investment in a drilling company for proceeds of $7.0 million and recognized a gain of $4.4 million. In addition, in the third quarter 2013 we sold unproved leases in West Texas for proceeds of $2.6 million where we recognized a gain of $1.7 million and sold surface acreage in North Texas for proceeds of $5.3 million with a loss of $253,000 recognized.
	In December 2012, we announced our plan to offer for sale certain of our Delaware and Permian Basin properties in southeast New Mexico and West Texas. On February 26, 2013, we announced we signed a definitive agreement to sell these assets for a price of $275.0 million, subject to normal post-closing adjustments. The agreement had an effective date of January 1, 2013 and consequently, operating net revenues after January 1, 2013 were a downward adjustment to the sales price. We closed this disposition on April 1 and we recognized a gain of approximately $83.5 million in second quarter 2013 related to this sale, before selling expenses of $4.2 million. Also in second quarter 2013, we received $14.2 million of proceeds from the sale of miscellaneous oil and gas properties in Pennsylvania and West Texas and we recognized a gain of $4.0 million on these transactions. In the first nine months 2013, we also received $10.0 million of proceeds from the sale of miscellaneous oil and gas property in Pennsylvania, with no gain or loss recognized.
	2012 Dispositions
	In September 2012, we sold unproved properties in three counties in Pennsylvania for proceeds of $13.9 million resulting in a pre-tax gain of $746,000. As part of this agreement, we retained an overriding royalty of 1% to 5% on a large portion of the leases.
	In June 2012, we sold a suspended well in the Marcellus Shale for proceeds of $2.5 million resulting in a pre-tax loss of $2.5 million. In March 2012, we sold seventy-five percent of a prospect in East Texas which included unproved properties and a suspended exploratory well to a third party for $8.6 million resulting in a pre-tax loss of $10.9 million. As part of this agreement, we retained a carried interest on the first well drilled and an overriding royalty of 2.5% to 5.0% in the prospect.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Taxes	(5) INCOME TAXES
	Income tax expense (benefit) from operations was as follows (in thousands):
		Three Months Ended							Nine Months Ended
		September 30,							September 30,
		2013			2012				2013			2012
	Income tax expense (benefit)	$	11,866		$	(29,074	)		$	62,180		$	(17,910	)
	Effective tax rate		38.2	%		35.1		%		41.5	%		30.9		%
	We compute our quarterly taxes under the effective tax rate method based on applying an anticipated annual effective rate to our year-to-date income, except for discrete items. Income taxes for discrete items are computed and recorded in the period that the specific transaction occurs. For third quarter and the nine months ended September 30, 2013 and 2012, our overall effective tax rate on operations was different than the federal statutory rate of 35% due primarily to state income taxes, valuation allowances and other permanent differences.

Income_Per_Common_Share

Income Per Common Share	9 Months Ended
	Sep. 30, 2013
Income (Loss) Per Common Share	(6) INCOME (LOSS) PER COMMON SHARE
	Basic income or loss per share attributable to common shareholders is computed as (1) income or loss attributable to common shareholders (2) less income allocable to participating securities (3) divided by weighted average basic shares outstanding. Diluted income or loss per share attributable to common stockholders is computed as (1) basic income or loss attributable to common shareholders (2) plus diluted adjustments to income allocable to participating securities (3) divided by weighted average diluted shares outstanding. The following tables set forth a reconciliation of income or loss attributable to common shareholders to basic income or loss attributable to common shareholders to diluted income or loss attributable to common shareholders (in thousands except per share amounts):
		Three Months Ended							Nine Months Ended
		September 30,							September 30,
		2013				2012			2013				2012
	Net income (loss), as reported	$		19,178		$	(53,836	)	$	87,551			$	(39,960	)
	Participating basic earnings (a)			(341	)		(119	)		(1,479	)			(348	)
	Basic net income (loss) attributed to common shareholders			18,837			(53,955	)		86,072				(40,308	)
	Reallocation of participating earnings (a)			1			—			6				—
	Diluted net income (loss) attributed to common shareholders	$		18,838		$	(53,955	)	$	86,078			$	(40,308	)
	Net income (loss) per common share:
	Basic	$		0.12		$	(0.34	)	$	0.54			$	(0.25	)
	Diluted	$		0.12		$	(0.34	)	$	0.53			$	(0.25	)
	(a)              Restricted Stock Awards represent participating securities because they participate in nonforfeitable dividends or distributions with common equity owners. Income allocable to participating securities represents the distributed and undistributed earnings attributable to the participating securities. Participating securities, however, do not participate in undistributed net losses.
	The following table provides a reconciliation of basic weighted average common shares outstanding to diluted weighted average common shares outstanding (in thousands):
		Three Months Ended										Nine Months Ended
		September 30,										September 30,
		2013					2012					2013				2012
	Denominator:
	Weighted average common shares outstanding – basic		160,500					159,563					160,398				159,297
	Effect of dilutive securities:
	Director and employee stock options and SARs		874					—					923				—
	Weighted average common shares outstanding – diluted		161,374					159,563					161,321				159,297
	Weighted average common shares – basic for the three months ended September 30, 2013 excludes 2.9 million shares and the three months ended September 30, 2012 excludes 3.0 million shares of restricted stock held in our deferred compensation plans (although all awards are issued and outstanding upon grant). Weighted average common shares – basic for the nine months ended September 30, 2013 excludes 2.8 million shares of restricted stock compared to 2.9 million in the same period of 2012. Stock appreciation rights (“SARs”) of 796 for the three months ended September 30, 2013 and 181,000 for the nine months ended September 30, 2013 were outstanding but not included in the computations of diluted income from operations per share because the grant prices of the SARs were greater than the average market price of the common shares. Due to our loss from continuing operations for the three months and the nine months ended September 30, 2012, we excluded all outstanding SARs and restricted stock from the computation of diluted net income (loss) per share because the effect would have been anti-dilutive to the computations.

Suspended_Exploratory_Well_Cos

Suspended Exploratory Well Costs	9 Months Ended
	Sep. 30, 2013
Suspended Exploratory Well Costs	(7) SUSPENDED EXPLORATORY WELL COSTS
	We capitalize exploratory well costs until a determination is made that the well has either found proved reserves or that it is impaired. Capitalized exploratory well costs are presented in natural gas and oil properties in the accompanying consolidated balance sheets. If an exploratory well is determined to be impaired, the well costs are charged to exploration expense in the accompanying consolidated statements of operations. The following table reflects the changes in capitalized exploratory well costs for the nine months ended September 30, 2013 and the year ended December 31, 2012 (in thousands except for number of projects):
		September 30,			December 31,
		2013			2012
	Balance at beginning of period	$	57,360		$	93,388
	Additions to capitalized exploratory well costs pending the determination of proved reserves		61,751			153,250
	Reclassifications to wells, facilities and equipment based on determination of proved reserves		(80,358	)		(184,298	)
	Capitalized exploratory well costs charged to expense		(3,950	)		
	Divested wells					(4,980	)
	Balance at end of period		34,803			57,360
	Less exploratory well costs that have been capitalized for a period of one year or less		(21,923	)		(45,965	)
	Capitalized exploratory well costs that have been capitalized for a period greater than	$	12,880		$	11,395
	one year
	Number of projects that have exploratory well costs that have been capitalized for a period greater than one year		4			5
	As of September 30, 2013, $12.9 million of capitalized exploratory well costs have been capitalized for more than one year which relates to two wells waiting on pipelines and two wells currently in the completion stage. One of the wells is not operated by us and all of the wells are in Pennsylvania. In 2012, we sold a seventy-five percent interest in an East Texas exploratory well. Refer to Note 4 for additional information.
	The following table provides an aging of capitalized exploratory well costs that have been suspended for more than one year as of September 30, 2013 (in thousands):
		Total			2013			2012		2011		2010		2009		2008
	Capitalized exploratory well costs that have been capitalized for more than one year	$	12,880		$	208		$	6,904	$	1,289	$	72	$	2,884	$	1,523

Indebtedness

Indebtedness	9 Months Ended
	Sep. 30, 2013
Indebtedness	(8) INDEBTEDNESS
	We had the following debt outstanding as of the dates shown below (in thousands) (bank debt interest rate at September 30, 2013 is shown parenthetically; no interest was capitalized during the three months or the nine months ended September 30, 2013 or 2012):
		September 30,		December 31,
		2013		2012
	Bank debt (1.9%)	$	427,000	$	739,000
	Senior subordinated notes:
	7.25% senior subordinated notes due 2018		—		250,000
	8.00% senior subordinated notes due 2019, net of $9,830 and $10,815 discount, respectively		290,170		289,185
	6.75% senior subordinated notes due 2020		500,000		500,000
	5.75% senior subordinated notes due 2021		500,000		500,000
	5.00% senior subordinated notes due 2022		600,000		600,000
	5.00% senior subordinated notes due 2023		750,000		—
	Total debt	$	3,067,170	$	2,878,185
	Bank Debt
	In February 2011, we entered into an amended and restated revolving bank facility, which we refer to as our bank debt or our bank credit facility, which is secured by substantially all of our assets. The bank credit facility provides for an initial commitment equal to the lesser of the facility amount or the borrowing base. On September 30, 2013, the facility amount was $1.75 billion and the borrowing base was $2.0 billion. The bank credit facility provides for a borrowing base subject to redeterminations semi-annually and for event-driven unscheduled redeterminations. As part of our semi-annual bank review completed on October 18, 2013, our borrowing base was reaffirmed at $2.0 billion and our facility amount was also reaffirmed at $1.75 billion. Our current bank group is composed of twenty-eight financial institutions with no one bank holding more than 9% of the total facility. The bank credit facility amount may be increased to the borrowing base amount with twenty days’ notice, subject to the banks agreeing to participate in the facility increase and payment of a mutually acceptable commitment fee to those banks. As of September 30, 2013, the outstanding balance under our bank credit facility was $427.0 million. Additionally, we had $84.9 million of undrawn letters of credit leaving $1.2 billion of borrowing capacity available under the facility. The bank credit facility matures on February 18, 2016. Borrowings under the bank credit facility can either be at the Alternate Base Rate (as defined in the bank credit facility) plus a spread ranging from 0.50% to 1.5% or LIBOR borrowings at the Adjusted LIBO Rate (as defined in the bank credit facility) plus a spread ranging from 1.5% to 2.5%. The applicable spread is dependent upon borrowings relative to the borrowing base. We may elect, from time to time, to convert all or any part of our LIBOR loans to base rate loans or to convert all or any of the base rate loans to LIBOR loans. The weighted average interest rate was 1.9% for the three months ended September 30, 2013 compared to 2.1% for the three months ended September 30, 2012. The weighted average interest rate was 2.0% for the nine months ended September 30, 2013 compared to 2.2% for the nine months ended September 30, 2012. A commitment fee is paid on the undrawn balance based on an annual rate of 0.35% to 0.50%. At September 30, 2013, the commitment fee was 0.375% and the interest rate margin was 1.5% on our LIBOR loans and 0.5% on our base rate loans.
	Senior Subordinated Notes
	In March 2013, we issued $750.0 million aggregate principal amount of 5.00% senior subordinated notes due 2023 (the “Outstanding Notes”) at par for net proceeds of $738.8 million after underwriting commissions of $11.2 million. The offering of the Outstanding Notes were only offered to qualified institutional buyers and to Non-U.S. persons outside the United States in compliance with Rule 144A and Regulation S under the Securities Act of 1933, as amended (the “Securities Act”). On June 19, 2013, substantially all of the Outstanding Notes were exchanged for an equal principal amount of registered 5.00% senior subordinated notes due 2023 pursuant to an effective registration statement on Form S-4 filed on April 26, 2013 under the Securities Act (the “Exchange Notes”). The Exchange Notes are identical to the Outstanding Notes except that the Exchange Notes are registered under the Securities Act and do not have restrictions on transfer, registration rights or provisions for additional interest. As used in this Form 10-Q, the term “5.00% Notes due 2023” refer to both the Outstanding Notes and the Exchange Notes. Interest on the 5.00% Notes due 2023 is payable semi-annually in March and September and is guaranteed by all of our subsidiary guarantors. We may redeem the 5.00% Notes due 2023, in whole or in part, at any time on or after March 15, 2018, at a redemption price of 102.5% of the principal amount as of March 15, 2018, declining to 100% on March 15, 2021 and thereafter. Before March 15, 2016, we may redeem up to 35% of the original aggregate principal amount of the 5.00% Notes due 2023 at a redemption price equal to 105% of the principal amount thereof, plus accrued and unpaid interest, if any, with the proceeds of certain equity offerings, provided that 65% of the aggregate principal amount of 5.00% Notes due 2023 remains outstanding immediately after the occurrence of such redemption and also provided such redemption shall occur within 60 days of the date of the closing of the equity offering. On closing of the 5.00% Notes due 2023, we used the proceeds to pay down our outstanding bank credit facility balance. We did not receive any proceeds from the issuance of the Exchange Notes.
	If we experience a change of control, bondholders may require us to repurchase all or a portion of all of our senior subordinated notes at 101% of the aggregate principal amount plus accrued and unpaid interest, if any. All of the senior subordinated notes and the guarantees by our subsidiary guarantors are general, unsecured obligations and are subordinated to our bank debt and will be subordinated to future senior debt that we or our subsidiary guarantors are permitted to incur under the bank credit facility and the indentures governing the subordinated notes.
	Early Extinguishment of Debt
	On April 2, 2013, we announced a call for the redemption of $250.0 million of our outstanding 7.25% senior subordinated notes due 2018 at 103.625% of par which were redeemed on May 2, 2013. In second quarter 2013, we recognized a $12.3 million loss on extinguishment of debt, including transaction call premium costs as well as expensing of the remaining deferred financing costs on the repurchased debt.
	Guarantees
	Range Resources Corporation is a holding company which owns no operating assets and has no significant operations independent of its subsidiaries. The guarantees by our subsidiaries of our senior subordinated notes are full and unconditional and joint and several, subject to certain customary release provisions. A subsidiary guarantor may be released from its obligations under the guarantee:
	in the event of a sale or other disposition of all or substantially all of the assets of the subsidiary guarantor or a sale or other disposition of all the capital stock of the subsidiary guarantor, to any corporation or other person (including an unrestricted subsidiary of Range) by way of merger, consolidation, or otherwise; or
	if Range designates any restricted subsidiary that is a guarantor to be an unrestricted subsidiary in accordance with the terms of the indenture.
	Debt Covenants and Maturity
	Our bank credit facility contains negative covenants that limit our ability, among other things, to pay cash dividends, incur additional indebtedness, sell assets, enter into certain hedging contracts, change the nature of our business or operations, merge, consolidate, or make investments. In addition, we are required to maintain a ratio of debt to EBITDAX (as defined in the credit agreement) of no greater than 4.25 to 1.0 and a current ratio (as defined in the credit agreement) of no less than 1.0 to 1.0. We are in compliance with our covenants under the bank credit facility at September 30, 2013.
	The indentures governing our senior subordinated notes contain various restrictive covenants that are substantially identical to each other and may limit our ability to, among other things, pay cash dividends, incur additional indebtedness, sell assets, enter into transactions with affiliates, or change the nature of our business. At September 30, 2013, we are in compliance with these covenants.

Asset_Retirement_Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligations	(9) ASSET RETIREMENT OBLIGATIONS
	Our asset retirement obligations primarily represent the estimated present value of the amounts we will incur to plug, abandon and remediate our producing properties at the end of their productive lives. Significant inputs used in determining such obligations include estimates of plugging and abandonment costs, estimated future inflation rates and well life. The inputs are calculated based on historical data as well as current estimated costs. A reconciliation of our liability for plugging and abandonment costs for the nine months ended September 30, 2013 is as follows (in thousands):
		Nine Months
		Ended
		September 30, 2013
	Beginning of period	$	146,478
	Liabilities incurred		5,267
	Liabilities settled		(398	)
	Disposition of wells		(3,104	)
	Accretion expense		8,011
	Change in estimate		(6,231	)
	End of period		150,023
	Less current portion		(2,366	)
	Long-term asset retirement obligations	$	147,657
	Accretion expense is recognized as a component of depreciation, depletion and amortization expense in the accompanying statements of operations.

Capital_Stock

Capital Stock	9 Months Ended
	Sep. 30, 2013
Capital Stock	(10) CAPITAL STOCK
	We have authorized capital stock of 485.0 million shares which includes 475.0 million shares of common stock and 10.0 million shares of preferred stock. We currently have no preferred stock issued or outstanding. The following is a schedule of changes in the number of common shares outstanding since the beginning of 2012:
		Nine Months	Year
		Ended	Ended
		September 30,	December 31,
		2013	2012
	Beginning balance	162,514,098	161,131,547
	Stock options/SARs exercised	257,103	926,425
	Restricted stock granted	401,122	354,674
	Restricted stock units vested	118,324	57,824
	Treasury shares issued	26,497	43,628
	Ending balance	163,317,144	162,514,098

Derivative_Activities

Derivative Activities	9 Months Ended
	Sep. 30, 2013
Derivative Activities	(11) DERIVATIVE ACTIVITIES
	We use commodity-based derivative contracts to manage exposure to commodity price fluctuations. We do not enter into these arrangements for speculative or trading purposes. We do not utilize complex derivatives as we typically utilize commodity swaps or collars to (1) reduce the effect of price volatility of the commodities we produce and sell and (2) support our annual capital budget and expenditure plans. In 2011, we sold NGLs derivative swap contracts (“sold swaps”) for the natural gasoline (or C5) component of natural gas liquids and in 2012, we entered into purchased derivative swaps (“re-purchased swaps”) for C5 volumes. These re-purchased swaps were, in some cases, with the same counterparties as our sold swaps. We entered into these re-purchased swaps to lock in certain natural gasoline derivative gains. In second quarter 2012, we entered into NGLs derivative swap contracts for the propane (or C3) component of NGLs and in third quarter 2013, we also entered into NGLs derivative swap contracts for the normal butane (or C4) component of NGLs. The fair value of our derivative contracts, represented by the estimated amount that would be realized upon termination, based on a comparison of the contract price and a reference price, generally the New York Mercantile Exchange (“NYMEX”), approximated a net unrealized pre-tax gain of $66.0 million at September 30, 2013. These contracts expire monthly through December 2015.
	The following table sets forth our derivative volumes by year as of September 30, 2013:
	Period		Contract Type		Volume Hedged		Weighted
							Average Hedge Price
	Natural Gas
	2013		Collars		280,000 Mmbtu/day		$ 4.59–$ 5.05
	2014		Collars		447,500 Mmbtu/day		$ 3.84–$ 4.48
	2015		Collars		145,000 Mmbtu/day		$ 4.07–$ 4.56
	2013		Swaps		293,370 Mmbtu/day		$	3.82
	2014		Swaps		30,000 Mmbtu/day		$	4.17
	2015		Swaps		7,500 Mmbtu/day		$	4.16
	Crude Oil
	2013		Collars		3,000 bbls/day		$ 90.60–$ 100.00
	2014		Collars		2,000 bbls/day		$ 85.55–$ 100.00
	2013		Swaps		6,825 bbls/day		$	96.79
	2014		Swaps		7,000 bbls/day		$	94.14
	2015		Swaps		2,000 bbls day		$	90.20
	NGLs (Natural Gasoline)
	2013		Sold Swaps		8,000 bbls/day		$	89.64
	2013		Re-purchased Swaps		1,500 bbls/day		$	76.30
	NGLs (Propane)
	2013		Swaps		11,000 bbls/day		$	37.87
	2014		Swaps		7,000 bbls/day		$	40.38
	NGLs (Normal butane)
	2013		Swaps		2,000 bbls/day		$	55.44
	2014		Swaps		2,000 bbls/day		$	54.60
	Every derivative instrument is required to be recorded on the balance sheet as either an asset or a liability measured at its fair value. Fair value is determined based on the difference between the fixed contract price and the underlying market price at the determination date. Through February 28, 2013, changes in the fair value of our derivatives that qualified for hedge accounting were recorded as a component of AOCI in the stockholders’ equity section of the accompanying consolidated balance sheets, which is later transferred to natural gas, NGLs and oil sales when the underlying physical transaction occurs and the hedging contract is settled. As of September 30, 2013, an unrealized pre-tax derivative gain of $32.3 million ($19.7 million after tax) was recorded in AOCI. See additional discussion below regarding the discontinuance of hedge accounting. If the derivative does not qualify as a hedge or is not designated as a hedge, changes in fair value of these non-hedge derivatives are recognized in earnings in derivative fair value income or loss.
	For those derivative instruments that qualified or were designated for hedge accounting, settled transaction gains and losses are determined monthly, and are included as increases or decreases to natural gas, NGLs and oil sales in the period the hedged production is sold. Through February 28, 2013, we had elected to designate our commodity derivative instruments that qualified for hedge accounting as cash flow hedges. Natural gas, NGLs and oil sales include $27.4 million of gains in third quarter 2013 compared to gains of $61.5 million in the same period of 2012 related to settled hedging transactions. Natural gas, NGLs and oil sales include $94.4 million of gains in the first nine months 2013 compared to gains of $197.7 million in the same period of 2012. Any ineffectiveness associated with these hedge derivatives is reflected in derivative fair value income or loss in the accompanying statements of operations. The ineffective portion is generally calculated as the difference between the changes in fair value of the derivative and the estimated change in future cash flows from the item hedged. Derivative fair value (loss) income for the three months ended September 30, 2013 includes ineffective losses (unrealized and realized) of $39,000 compared to a loss of $3.7 million in the three months ended September 30, 2012. Derivative fair value (loss) income for the nine months ended September 30, 2013 includes ineffective losses (unrealized and realized) of $2.9 million compared to a loss of $1.6 million in the same period of 2012. During the nine months ended September 30, 2013, we recognized a pre-tax gain of $3.9 million in derivative fair value (loss) income as a result of the discontinuance of hedge accounting where we determined the transaction was probable not to occur primarily due to the sale of our Delaware and Permian Basin properties in New Mexico and West Texas.
	Discontinuance of Hedge Accounting
	Effective March 1, 2013, we elected to de-designate all commodity contracts that were previously designated as cash flow hedges and elected to discontinue hedge accounting prospectively. AOCI included $103.6 million ($63.2 million after tax) of unrealized net gains, representing the marked-to-market value of the effective portion of our cash flow hedges as of February 28, 2013. As a result of discontinuing hedge accounting, the marked-to-market values included in AOCI as of the de-designation date were frozen and will be reclassified into earnings in natural gas, NGLs and oil sales in future periods as the underlying hedged transactions occur. As of September 30, 2013, we expect to reclassify into earnings $22.1 million of unrealized net gains in the remaining months of 2013 and $10.2 million of unrealized net gains in 2014 from AOCI.
	With the election to de-designate hedging instruments, all of our derivative instruments continue to be recorded at fair value with unrealized gains and losses recognized immediately in earnings rather than in AOCI. These marked-to-market adjustments will produce a degree of earnings volatility that can be significant from period to period, but such adjustments will have no cash flow impact relative to changes in market prices. The impact to cash flow occurs upon settlement of the underlying contract.
	Derivative Fair Value (Loss) Income
	The following table presents information about the components of derivative fair value (loss) income for the three months and the nine months ended September 30, 2013 and 2012 (in thousands):
				Three Months Ended									Nine Months Ended
				September 30,									September 30,
				2013					2012				2013					2012
	Change in fair value of derivatives that did not qualify or were not designated for hedge accounting (a)			$		(34,219	)		$		(53,646	)	$		28,350			$		30,075
	Realized gain (loss) on settlement–natural gas (a) (b)					5,815					—				(17,913	)				—
	Realized (loss) gain on settlement–oil (a) (b)					(8,005	)				1,955				(8,218	)				(1,899	)
	Realized (loss) gain on settlement–NGLs (a) (b)					(3,907	)				14,682				(1,759	)				20,442
	Hedge ineffectiveness		–realized			(854	)				988				(445	)				3,451
			–unrealized			815					(4,707	)			(2,485	)				(5,061	)
	Derivative fair value (loss) income			$		(40,355	)		$		(40,728	)	$		(2,470	)		$		47,008
	(a) Derivatives that did not qualify or were not designated for hedge accounting. Change in fair value of derivatives line also includes gains of $3.1 million in third quarter 2013 and gains of $25.5 million in the first nine months 2013 related to discontinuance of hedge accounting.
	(b) These amounts represent the realized gains and losses on settled derivatives that did not qualify or were not designated for hedge accounting, which before settlement are included in the category in this same table referred to as change in fair value of derivatives that did not qualify or were not designated for hedge accounting.
	Derivative Assets and Liabilities
	The combined fair value of derivatives included in the accompanying consolidated balance sheets as of September 30, 2013 and December 31, 2012 is summarized below. The assets and liabilities are netted where derivatives with both gain and loss positions are held by a single counterparty and we have master netting arrangements.
	The tables below provide additional information relating to our master netting arrangements with our derivative counterparties (in thousands):
				September 30, 2013
				Gross Amounts of					Gross Amounts				Net Amounts of
				Recognized Assets					Offset in the				Assets Presented in the
									Balance Sheet				Balance Sheet
	Derivative assets:
	Natural gas		–swaps	$		10,965			$		(2,046	)	$		8,919
			–collars			71,699					(1,720	)			69,979
	Crude oil		–swaps			2,962					(7,766	)			(4,804		)
			–collars			137					(1,803	)			(1,666		)
	NGLs		–C5 swaps			3,374					(1,461	)			1,913
			–C3 swaps			7					(552	)			(545		)
			–C4 swaps			406					(135	)			271
				$		89,550			$		(15,483	)	$		74,067
				30-Sep-13
				Gross Amounts of					Gross Amounts				Net Amounts of
Recognized (Liabilities)				Offset in the					(Liabilities) Presented in the
				Balance Sheet					Balance Sheet
Derivative (liabilities):
Natural gas		–swaps	$		(1,219	)		$		2,046		$		827
		–collars			(1,720	)				1,720				—
Crude oil		–swaps			(7,766	)				7,766				—
		–collars			(1,803	)				1,803				—
NGLs		–C5 swaps			(9	)				1,461				1,452
		–C3 swaps			(10,469	)				552				(9,917		)
		–C4 swaps			(571	)				135				(436		)
			$		(23,557	)		$		15,483		$		(8,074		)
			December 31, 2012
			Gross Amounts of					Gross Amounts				Net Amounts of
			Recognized Assets					Offset in the				Assets Presented in the
								Balance Sheet				Balance Sheet
Derivative assets:
Natural gas		–swaps	$		10,746			$		(3,242	)	$		7,504
		–collars			128,410					(6,155	)			122,255
		–basis swaps			993					—				993
Crude oil		–swaps			9,650					—				9,650
		–collars			2,222					—				2,222
NGLs		–C5  swaps			13,055					(2,412	)			10,643
			$		165,076			$		(11,809	)	$		153,267
			31-Dec-12
			Gross Amounts of					Gross Amounts							Net Amounts of
			Recognized (Liabilities)					Offset in the							(Liabilities) Presented in the
								Balance Sheet							Balance Sheet
Derivative (liabilities):
Natural gas		–swaps	$		(3,242	)			$		(221	)				$		(3,463		)
		–collars			(9,618	)					9,618							—
NGLs		–C5 swaps			(137	)					2,412							2,275
		–C3 swaps			(6,746	)					—							(6,746		)
			$		(19,743	)			$		11,809					$		(7,934		)
The table below provides data about the fair value of our derivative contracts. Derivative assets and liabilities shown below are presented as gross assets and liabilities, without regard to master netting arrangements, which are considered in the presentation of derivative assets and liabilities in the accompanying consolidated balance sheets (in thousands):
	September 30, 2013																December 31, 2012
	Assets					(Liabilities)												Assets					(Liabilities)
	Carrying					Carrying					Net							Carrying					Carrying						Net
	Value					Value					Carrying							Value					Value						Carrying
											Value																		Value
Derivatives that qualified for cash flow hedge accounting (before discontinuance of hedge accounting):
Swaps (a)	$		7,091			$		(3,960	)		$	3,131						$		22,236			$		(3,242		)			$		18,994
Collars (a)			38,685					(10,356	)			28,329								129,878					(9,721		)					120,157
	$		45,776			$		(14,316	)		$	31,460						$		152,114			$		(12,963		)			$		139,151
Derivatives that did not qualify or were not designated for hedge accounting:
Sold swaps (a)	$		16,159			$		(23,072	)		$	(6,913		)				$		7,316			$		(8,904		)			$		(1,588	)
Re-purchased swaps (a)			1,462					—				1,462								5,920					—							5,920
Collars (a)			42,943					(2,959	)			39,984								857					—							857
Basis swaps (a)			—					—				—								993					—							993
	$		60,564			$		(26,031	)		$	34,533						$		15,086			$		(8,904		)			$		6,182
(a) Included in unrealized derivatives in the accompanying consolidated balance sheets. See additional discussion above regarding the discontinuance of hedge accounting.
The effects of our cash flow hedges (or those derivatives that previously qualified for hedge accounting) on accumulated other comprehensive income in the accompanying consolidated balance sheets is summarized below (in thousands):
	Three Months Ended September 30,																							Nine Months Ended September 30,
	Change in Hedge										Realized Gain (Loss)											Change in Hedge													Realized Gain (Loss)
	Derivative Fair Value										Reclassified from OCI											Derivative Fair Value													Reclassified from OCI
											into Revenue (a)																								into Revenue (a)
	2013					2012					2013				2012							2013						2012							2013						2012
Swaps	$		—			$		(33,311	)		$	2,765			$		18,204					$				125		$		22,525			$			14,687			$				69,851
Put options			—					(994	)			—					(682	)								—				(1,908	)					—							(998	)
Collars			—					(51,344	)			25,357					43,945									(7,015	)			32,704						83,630							128,823
Income taxes			—					33,403				(10,967	)				(23,972	)								2,687				(21,780	)					(38,343	)						(76,805	)
	$		—			$		(52,246	)		$	17,155			$		37,495					$				(4,203	)	$		31,541			$			59,974			$				120,871
(a) For realized gains upon derivative contract settlement, the reduction in AOCI is offset by an increase in revenues, NGLs and oil sales. For realized losses upon derivative contract settlement, the increase in AOCI is offset by a decrease in revenues. See additional discussion above regarding the discontinuance of hedge accounting.
The effects of our non-hedge derivatives (or those derivatives that do not qualify for hedge accounting) and the ineffective portion of our hedge derivatives on our consolidated statements of operations is summarized below (in thousands):
	Three Months Ended September 30,
	Gain (Loss) Recognized in																Gain (Loss) Recognized in																Derivative Fair Value
	Income (Non‑hedge Derivatives)																Income (Ineffective Portion)																Income (Loss)
	2013							2012										2013								2012								2013					2012
Swaps	$		(48,277		)				$		(45,998		)						$		(39		)				$	(1,556			)				$	(48,316		)		$		(47,554			)
Re-purchased swaps			1,595								12,822										—							—								1,595						12,822
Collars			6,366								(1,714		)								—							(2,163			)					6,366						(3,877			)
Call options			—								(2,119		)								—							—								—						(2,119			)
Total	$		(40,316		)				$		(37,009		)						$		(39		)				$	(3,719			)				$	(40,355		)		$		(40,728			)
	Nine Months Ended September 30,
	Gain (Loss) Recognized in																Gain (Loss) Recognized in																Derivative Fair Value
	Income (Non‑hedge Derivatives)																Income (Ineffective Portion)																Income (Loss)
	2013							2012										2013								2012								2013					2012
Swaps	$		(26,350		)				$		30,330								$		(2,034		)				$	(890			)				$	(28,384		)		$		29,440
Re-purchased swaps			1,117								4,078										—							—								1,117						4,078
Collars			25,783								3,381										(896		)					(720			)					24,887						2,661
Call options			—								10,829										—							—								—						10,829
Basis swaps			(90		)						—																	—								(90		)				—
Total	$		460						$		48,618								$		(2,930		)				$	(1,610			)				$	(2,470		)		$		47,008

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Measurements	(12) FAIR VALUE MEASUREMENTS
	Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. There are three approaches for measuring the fair value of assets and liabilities: the market approach, the income approach and the cost approach, each of which includes multiple valuation techniques. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. The income approach uses valuation techniques to measure fair value by converting future amounts, such as cash flows or earnings, into a single present value amount using current market expectations about those future amounts. The cost approach is based on the amount that would currently be required to replace the service capacity of an asset. This is often referred to as current replacement cost. The cost approach assumes that the fair value would not exceed what it would cost a market participant to acquire or construct a substitute asset of comparable utility, adjusted for obsolescence.
	The fair value accounting standards do not prescribe which valuation technique should be used when measuring fair value and does not prioritize among the techniques. These standards establish a fair value hierarchy that prioritizes the inputs used in applying the various valuation techniques. Inputs broadly refer to the assumptions that market participants use to make pricing decisions, including assumptions about risk. Level 1 inputs are given the highest priority in the fair value hierarchy while Level 3 inputs are given the lowest priority. The three levels of the fair value hierarchy are as follows:
	Level 1 – Observable inputs that reflect unadjusted quoted prices for identical assets or liabilities in active markets as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis.
	Level 2 – Observable market-based inputs or unobservable inputs that are corroborated by market data. These are inputs other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date.
	Level 3 – Unobservable inputs that are not corroborated by market data and may be used with internally developed methodologies that result in management’s best estimate of fair value.
	Valuation techniques that maximize the use of observable inputs are favored. Assets and liabilities are classified in their entirety based on the lowest priority level of input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the placement of assets and liabilities within the levels of the fair value hierarchy.
	Fair Values – Recurring
	We use a market approach for our recurring fair value measurements and endeavor to use the best information available. The following tables present the fair value hierarchy table for assets and liabilities measured at fair value, on a recurring basis (in thousands):
				Fair Value Measurements at September 30, 2013 using:
				Quoted Prices					Significant				Significant					Total
				in Active					Other				Unobservable					Carrying
				Markets for					Observable				Inputs					Value as of
				Identical Assets					Inputs				(Level 3)					September 30,
				(Level 1)					(Level 2)									2013
	Trading securities held in the deferred compensation plans			$		65,663			$		—		$		—			$		65,663
	Derivatives		–swaps			—					(2,320	)			—					(2,320		)
			–collars			—					68,313				—					68,313
				Fair Value Measurements at December 31, 2012 using:
				Quoted Prices									Significant										Significant				Total
				in Active									Other										Unobservable				Carrying
				Markets for									Observable										Inputs				Value as of
				Identical Assets									Inputs										(Level 3)				December 31,
				(Level 1)									(Level 2)														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
	Our trading securities in Level 1 are exchange-traded and measured at fair value with a market approach using end of period market values. Derivatives in Level 2 are measured at fair value with a market approach using third-party pricing services, which have been corroborated with data from active markets or broker quotes.
	Our trading securities held in the deferred compensation plan are accounted for using the mark-to-market accounting method and are included in other assets in the accompanying consolidated balance sheets. We elected to adopt the fair value option to simplify our accounting for the investments in our deferred compensation plan. Interest, dividends, and mark-to-market gains or losses are included in deferred compensation plan expense in the accompanying statement of operations. For third quarter 2013, interest and dividends were $111,000 and the mark-to-market adjustment was a gain of $3.2 million compared to interest and dividends of $122,000 and mark-to-market gain of $3.8 million in the same period of the prior year. For nine months ended September 30, 2013, interest and dividends were $779,000 and the mark-to-market adjustment was a gain of $3.8 million compared to interest and dividends of $279,000 and a mark-to-market gain of $5.7 million in the same period of the prior year.
	Fair Values—Non-recurring
	We review our long-lived assets to be held and used for impairment including proved natural gas and oil properties, whenever events or circumstances indicate the carrying value of those assets may not be recoverable. In third quarter 2013, we recognized an impairment expense of $7.0 million on certain of our oil and gas properties in South Texas due to reduction in reserves due to a failed well recompletion. Their fair value was measured using an income approach based upon internal estimates of future production levels, drilling and operating costs as well as discount rates, which are Level 3 inputs.  In second quarter 2013, we evaluated certain surface property we own which included consideration of the potential sale of the assets and recognized an impairment charge of $741,000. The following table presents the fair value of these assets at September 30, 2013 measured at fair value on a non-recurring basis (in thousands):
		Three Months Ended																			Nine Months Ended
		September 30,																			September 30,
		2013										2012									2013							2012
				Fair Value					Impairment				Fair Value					Impairment					Fair Value			Impairment			Fair Value			Impairment
	Natural gas and oil properties	$		500			$		7,012			$	—			$		—			$		500	$		7,012	$		—		$	—
	Surface property	$		—			$		—			$	6,269			$		1,281			$		—	$		741	$		6,269		$	1,281
	Fair Values—Reported
	The following table presents the carrying amounts and the fair values of our financial instruments as of September 30, 2013 and December 31, 2012 (in thousands):
		September 30, 2013										December 31, 2012
		Carrying					Fair					Carrying				Fair
		Value					Value					Value				Value
	Assets:
	Commodity swaps and collars	$		74,067			$		74,067			$	153,267			$		153,267
	Marketable securities(a)			65,663					65,663				57,776					57,776
	Liabilities:
	Commodity swaps and collars			(8,074	)				(8,074	)			(7,934	)				(7,934	)
	Bank credit facility(b)			(427,000	)				(427,000	)			(739,000	)				(739,000	)
	Deferred compensation plan(c)			(207,404	)				(204,404	)			(187,604	)				(187,604	)
	7.25% senior subordinated notes due 2018(b)			—					—				(250,000	)				(262,500	)
	8.00% senior subordinated notes due 2019(b)			(290,170	)				(322,125	)			(289,185	)				(332,250	)
	6.75% senior subordinated notes due 2020(b)			(500,000	)				(538,750	)			(500,000	)				(542,500	)
	5.75% senior subordinated notes due 2021(b)			(500,000	)				(525,000	)			(500,000	)				(535,000	)
	5.00% senior subordinated notes due 2022(b)			(600,000	)				(580,500	)			(600,000	)				(627,000	)
	5.00% senior subordinated notes due 2023(b)			(750,000	)				(720,000	)			—					—
	(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 which is a Level 1 market value.
	Our current assets and liabilities contain financial instruments, the most significant of which are trade accounts receivable and payable. We believe the carrying values of our current assets and liabilities approximate fair value. Our fair value assessment incorporates a variety of considerations including (1) the short-term duration of the instruments and (2) our historical incurrence of and expected future insignificance of bad debt expense. Non-financial liabilities initially measured at fair value include asset retirement obligations. Refer to Note 9 for additional information.
	Concentrations of Credit Risk
	As of September 30, 2013, our primary concentrations of credit risk are the risks of collecting accounts receivable and the risk of counterparties’ failure to perform under derivative obligations. Most of our receivables are from a diverse group of companies, including major energy companies, pipeline companies, local distribution companies, financial institutions and end-users in various industries. Letters of credit or other appropriate security are obtained as deemed necessary to limit our risk of loss. Our allowance for uncollectible receivables was $2.5 million at September 30, 2013 and $2.4 million at December 31, 2012. As of September 30, 2013, our derivative contracts consist of swaps and collars. Our exposure to credit risk is diversified primarily among major investment grade financial institutions, the majority of which we have master netting agreements which provide for offsetting payables against receivables from separate derivative contracts. To manage counterparty risk associated with our derivatives, we select and monitor our counterparties based on our assessment of their financial strength and/or credit ratings. We may also limit the level of exposure with any single counterparty. At September 30, 2013, our derivative counterparties include fifteen financial institutions, of which all but two are secured lenders in our bank credit facility. At September 30, 2013, our net derivative assets include a net payable to the two counterparties not included in our bank credit facility of $53,000. For those counterparties that are not secured lenders in our bank credit facility or for which we do not have master netting arrangements, net derivative asset values are determined, in part, by reviewing credit default swap spreads for such counterparties. Net derivative liabilities are determined, in part, by using our market-based credit spread. None of our derivative contracts have margin requirements or collateral provisions that would require funding prior to the scheduled cash settlement date. We have also entered into the International Swaps and Derivatives Association Master Agreements (“ISDA Agreements”) with our counterparties. The terms of the ISDA Agreements provide us and our counterparties with rights of set off upon the occurrence of defined acts of default by either us or a counterparty to a derivative, whereby the party not in default may set off all derivative liabilities owed to the defaulting party against all derivative asset receivables from the defaulting party. We continue to monitor developments surrounding the derivative regulations adopted under the Dodd-Frank Wall Street Reform and Consumer Protection Act. We do not anticipate any significant changes to our hedging program as a result of this law.

StockBased_Compensation_Plans

Stock-Based Compensation Plans	9 Months Ended
	Sep. 30, 2013
Stock-Based Compensation Plans	(13) STOCK-BASED COMPENSATION PLANS
	Stock-Based Awards
	Stock options represent the right to purchase shares of stock in the future at the fair value of the stock on the date of grant. Most stock options granted under our stock option plans vest over a three-year period and expire five years from the date they are granted. Beginning in 2005, we began granting SARs to reduce the dilutive impact of our equity plans. Similar to stock options, SARs represent the right to receive a payment equal to the excess of the fair market value of shares of common stock on the date the right is exercised over the value of the stock on the date of grant. All SARs granted under the 2005 Plan will be settled in shares of stock, vest over a three-year period and have a maximum term of five years from the date they are granted. Beginning in first quarter 2011, the Compensation Committee of the Board of Directors also began granting restricted stock units under our equity-based stock compensation plans. These restricted stock units, which we refer to as restricted stock Equity Awards, vest over a three-year period. All awards granted have been issued at prevailing market prices at the time of grant and the vesting of these shares is based upon an employee’s continued employment with us.
	The Compensation Committee also grants restricted stock to certain employees and non-employee directors of the Board of Directors as part of their compensation. Upon grant of these restricted shares, which we refer to as restricted stock Liability Awards, the shares generally are placed in our deferred compensation plan and, upon vesting, employees are allowed to take withdrawals either in cash or in stock. Compensation expense is recognized over the balance of the vesting period, which is typically three years for employee grants and immediate vesting for non-employee directors. All restricted stock awards are issued at prevailing market prices at the time of the grant and vesting is based upon an employee’s continued employment with us. Prior to vesting, all restricted stock awards have the right to vote such shares and receive dividends thereon. These Liability Awards are classified as a liability and are remeasured at fair value each reporting period. This mark-to-market adjustment is reported as deferred compensation plan expense in the accompanying consolidated statements of operations.
	Total Stock-Based Compensation Expense
	Stock-based compensation represents amortization of restricted stock, restricted stock units and SARs expense. Unlike the other forms of stock-based compensation, the mark-to-market adjustment of the liability related to the vested restricted stock held in our deferred compensation plans is directly tied to the change in our stock price and not directly related to the functional expenses and therefore, is not allocated to the functional categories.
	The following table details the allocation of stock-based compensation that is allocated to functional expense categories (in thousands):
		Three Months Ended								Nine Months Ended
		September 30,								September 30,
		2013					2012			2013					2012
	Operating expense	$		699			$		598	$		2,056			$		1,647
	Brokered natural gas and marketing expense			531					452			1,310					1,313
	Exploration expense			983					1,126			3,013					3,048
	General and administrative expense			11,031					10,057			34,600					30,755
	Total	$		13,244			$		12,233	$		40,979			$		36,763
	Stock and Option Plans
	We have two active equity-based stock plans, the 2005 Plan and the Director Plan. Under these plans, incentive and non-qualified stock options, SARs, restricted stock units and various other awards may be issued to non-employee directors and employees pursuant to decisions of the Compensation Committee, which is comprised of only non-employee, independent directors. Of the 2.6 million grants outstanding at September 30, 2013, all are grants relating to SARs. Information with respect to SARs activity is summarized below:
		Shares			Weighted
					Average
					Exercise Price
	Outstanding at December 31, 2012	3,433,362			$		52.52
	Granted	470,617					75.82
	Exercised	(1,205,186	)				53.78
	Expired/forfeited	(50,974	)				53.69
	Outstanding at September 30, 2013	2,647,819			$		56.00
	Stock Appreciation Right Awards
	During first nine months 2013, we granted SARs to officers and non-officer employees. The weighted average grant date fair value per share of these SARs, based on our Black-Scholes-Merton assumptions, is shown below:
		Nine Months
		Ended
		September 30,
		2013
	Weighted average exercise price per share	$		75.82
	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	$		20.20
	Restricted Stock Awards
	Equity Awards
	In first nine months 2013, we granted 394,100 restricted stock Equity Awards to employees at an average grant price of $71.13 compared to 359,700 restricted stock Equity Awards granted to employees at an average grant price of $63.37 in the same period of 2012. These awards generally vest over a three-year period. We recorded compensation expense for these Equity Awards of $14.6 million in the first nine months 2013 compared to $8.2 million in the same period of 2012. Equity Awards are not issued to employees until they are vested. Employees do not have the option to receive cash.
	Liability Awards
	In first nine months 2013, we granted 406,300 shares of restricted stock Liability Awards as compensation to employees at an average price of $75.45 with vesting generally over a three-year period and 18,300 shares were granted to non-employee directors at an average price of $77.26 with immediate vesting. In the same period of 2012, we granted 365,000 shares of Liability Awards as compensation to employees at an average price of $63.88 with vesting generally over a three-year period and 14,700 shares were granted to non-employee directors at an average price of $64.35 with immediate vesting. We recorded compensation expense for Liability Awards of $16.0 million in first nine months 2013 compared to $15.2 million in the same period of 2012. Substantially all of these awards are held in our deferred compensation plan, are classified as a liability and are remeasured at fair value each reporting period. This mark-to-market adjustment is reported as deferred compensation expense in our consolidated statements of operations (see additional discussion below). A summary of the status of our non-vested restricted stock and restricted stock units outstanding at September 30, 2013 is summarized below:
		Equity Awards										Liability Awards
		Shares				Weighted					Shares					Weighted
						Average Grant										Average Grant
						Date Fair Value										Date Fair Value
	Outstanding at December 31, 2012		349,156			$		59.08					423,478			$		58.91
	Granted		394,053					71.13					424,624					75.53
	Vested		(235,580	)				62.30					(267,621	)				62.07
	Forfeited		(45,589	)				65.32					(21,704	)				57.31
	Outstanding at September 30, 2013		462,040			$		67.11					558,777			$		70.09
	Deferred Compensation Plan
	Our deferred compensation plan gives non-employee directors, officers and key employees the ability to defer all or a portion of their salaries and bonuses and invest in Range common stock or make other investments at the individual’s discretion. Range provides a partial matching contribution which vests over three years. The assets of the plans are held in a grantor trust, which we refer to as the Rabbi Trust, and are therefore available to satisfy the claims of our general creditors in the event of bankruptcy or insolvency. Our stock held in the Rabbi Trust is treated as a liability award as employees are allowed to take withdrawals from the Rabbi Trust either in cash or in Range stock. The liability for the vested portion of the stock held in the Rabbi Trust is reflected as deferred compensation liability in the accompanying consolidated balance sheets and is adjusted to fair value each reporting period by a charge or credit to deferred compensation plan expense on our consolidated statements of operations. The assets of the Rabbi Trust, other than our common stock, are invested in marketable securities and reported at their market value as other assets in the accompanying consolidated balance sheets. The deferred compensation liability reflects the vested market value of the marketable securities and Range stock held in the Rabbi Trust. Changes in the market value of the marketable securities and changes in the fair value of the deferred compensation plan liability are charged or credited to deferred compensation plan expense each quarter. We recorded mark-to-market income of $2.2 million in third quarter 2013 compared to mark-to-market loss of $20.1 million in third quarter 2012. We recorded mark-to-market loss of $33.3 million in the nine months ended September 30, 2013 compared to $21.6 million in the same period of 2012. The Rabbi Trust held 2.9 million shares (2.3 million of vested shares) of Range stock at September 30, 2013 compared to 2.7 million shares (2.3 million of vested shares) at December 31, 2012.

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2013
Supplemental Cash Flow Information	(14) SUPPLEMENTAL CASH FLOW INFORMATION
		Nine Months Ended
		September 30,
		2013			2012
		(in thousands)
	Net cash provided from operating activities included:
	Income taxes (refunded) paid to taxing authorities	$	(237	)	$	436
	Interest paid		129,043			99,828
	Non-cash investing and financing activities included:
	Asset retirement costs (removed) capitalized, net		(964	)		29,695
	Increase in accrued capital expenditures		32,776			6,605

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies	(15) COMMITMENTS AND CONTINGENCIES
	Litigation
	James A. Drummond and Chris Parrish v. Range Resources-Midcontinent, LLC et al.; pending in the District Court of Grady County, State of Oklahoma; Case No. CJ-2010-510
	As we previously disclosed, the parties successfully mediated the case in May 2013 resulting in a settlement and we executed a Stipulation and Agreement of Settlement, with an effective date of May 31, 2013, providing for a cash payment to the class in the amount of $87.5 million in settlement of all claims made by the class for the period prior to May 31, 2013. Pursuant to the settlement agreement, on June 28, 2013, we paid $87.5 million into an escrow account. On September 9, 2013, the Court approved the settlement thereby finally concluding this matter.
	We are the subject of, or party to, a number of other pending or threatened legal actions, administrative proceedings and claims arising in the ordinary course of our business. While many of these matters involve inherent uncertainty, we believe that the amount of the liability, if any, ultimately incurred with respect to proceedings or claims will not have a material adverse effect on our consolidated financial position as a whole or on our liquidity, capital resources or future annual results of operations. We will continue to evaluate our litigation quarterly and will establish and adjust any litigation reserves as appropriate to reflect our assessment of the then current status of litigation.
	Transportation and Gathering Contracts
	In the nine months ended September 30, 2013, our transportation and gathering commitments increased by approximately $150.0 million over the next 10 years primarily due to increases in existing transportation and gathering contracts.

Capitalized_Costs_and_Accumula

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization	9 Months Ended
	Sep. 30, 2013
Capitalized Costs and Accumulated Depreciation, Depletion and Amortization	(16) Capitalized Costs and Accumulated Depreciation, Depletion and Amortization (a)
		September 30,			December 31,
		2013			2012
		(in thousands)
	Natural gas and oil properties:
	Properties subject to depletion	$	7,919,627		$	7,368,308
	Unproved properties		748,055			743,467
	Total		8,667,682			8,111,775
	Accumulated depreciation, depletion and amortization		(2,160,378	)		(2,015,591	)
	Net capitalized costs	$	6,507,304		$	6,096,184
	(a) Includes capitalized asset retirement costs and the associated accumulated amortization.

Costs_Incurred_for_Property_Ac

Costs Incurred for Property Acquisition, Exploration and Development	9 Months Ended
	Sep. 30, 2013
Costs Incurred for Property Acquisition, Exploration and Development	(17) Costs Incurred for Property Acquisition, Exploration and Development (a)
		Nine			Year
		Months Ended			Ended
		September 30,			December 31,
		2013			2012
		(in thousands)
	Acreage purchases	$	69,987		$	188,843
	Development		727,386			1,049,129
	Exploration:
	Drilling		173,298			309,816
	Expense		47,331			65,758
	Stock-based compensation expense		3,013			4,049
	Gas gathering facilities:
	Development		40,626			41,035
	Subtotal		1,061,641			1,658,630
	Asset retirement obligations		(964	)		57,982
	Total costs incurred	$	1,060,677		$	1,716,612
	(a)              Includes cost incurred whether capitalized or expensed.

New_Accounting_Standards_Polic

New Accounting Standards (Policies)	9 Months Ended
	Sep. 30, 2013
Disclosures about Offsetting Assets and Liabilities	In December 2011, the Financial Accounting Standards Board (the “FASB”) issued ASU No. 2011-11, “Disclosures about Offsetting Assets and Liabilities,” requiring additional disclosures about offsetting and related arrangements. ASU 2011-11 is effective retrospectively for annual reporting periods beginning on or after January 1, 2013. Also, in January 2013, the FASB issued ASU No. 2013-01, “Balance Sheet (Topic 210):  Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities.” ASU 2013-01 revised and clarified the disclosures required by ASU No. 2011-11. We adopted these new requirements in first quarter 2013 and they did not have a material effect on our consolidated financial statements.
Comprehensive Income	In February 2013, the FASB issued ASU No. 2013-02, “Comprehensive Income (Topic 220): Reporting of Amounts Reclassified out of Accumulated Other Comprehensive Income.” ASU 2013-02 requires information to be disclosed about the amounts reclassified out of AOCI by component. We adopted this new requirement in first quarter 2013 and it did not have a material effect on our consolidated financial statements.

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2013
Income Tax Expense from Continuing Operations	Income tax expense (benefit) from operations was as follows (in thousands):
		Three Months Ended							Nine Months Ended
		September 30,							September 30,
		2013			2012				2013			2012
	Income tax expense (benefit)	$	11,866		$	(29,074	)		$	62,180		$	(17,910	)
	Effective tax rate		38.2	%		35.1		%		41.5	%		30.9		%

Income_Per_Common_Share_Tables

Income Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2013
Computations of Basic and Diluted (Loss) Income Per Common Share	Basic income or loss per share attributable to common shareholders is computed as (1) income or loss attributable to common shareholders (2) less income allocable to participating securities (3) divided by weighted average basic shares outstanding. Diluted income or loss per share attributable to common stockholders is computed as (1) basic income or loss attributable to common shareholders (2) plus diluted adjustments to income allocable to participating securities (3) divided by weighted average diluted shares outstanding. The following tables set forth a reconciliation of income or loss attributable to common shareholders to basic income or loss attributable to common shareholders to diluted income or loss attributable to common shareholders (in thousands except per share amounts):
		Three Months Ended							Nine Months Ended
		September 30,							September 30,
		2013				2012			2013				2012
	Net income (loss), as reported	$		19,178		$	(53,836	)	$	87,551			$	(39,960	)
	Participating basic earnings (a)			(341	)		(119	)		(1,479	)			(348	)
	Basic net income (loss) attributed to common shareholders			18,837			(53,955	)		86,072				(40,308	)
	Reallocation of participating earnings (a)			1			—			6				—
	Diluted net income (loss) attributed to common shareholders	$		18,838		$	(53,955	)	$	86,078			$	(40,308	)
	Net income (loss) per common share:
	Basic	$		0.12		$	(0.34	)	$	0.54			$	(0.25	)
	Diluted	$		0.12		$	(0.34	)	$	0.53			$	(0.25	)
	(a)              Restricted Stock Awards represent participating securities because they participate in nonforfeitable dividends or distributions with common equity owners. Income allocable to participating securities represents the distributed and undistributed earnings attributable to the participating securities. Participating securities, however, do not participate in undistributed net losses.
Basic Weighted Average Common Shares Outstanding to Diluted Weighted Average Common Shares Outstanding	The following table provides a reconciliation of basic weighted average common shares outstanding to diluted weighted average common shares outstanding (in thousands):
		Three Months Ended										Nine Months Ended
		September 30,										September 30,
		2013					2012					2013				2012
	Denominator:
	Weighted average common shares outstanding – basic		160,500					159,563					160,398				159,297
	Effect of dilutive securities:
	Director and employee stock options and SARs		874					—					923				—
	Weighted average common shares outstanding – diluted		161,374					159,563					161,321				159,297

Suspended_Exploratory_Well_Cos1

Suspended Exploratory Well Costs (Tables)	9 Months Ended
	Sep. 30, 2013
Suspended Exploratory Well Costs	We capitalize exploratory well costs until a determination is made that the well has either found proved reserves or that it is impaired. Capitalized exploratory well costs are presented in natural gas and oil properties in the accompanying consolidated balance sheets. If an exploratory well is determined to be impaired, the well costs are charged to exploration expense in the accompanying consolidated statements of operations. The following table reflects the changes in capitalized exploratory well costs for the nine months ended September 30, 2013 and the year ended December 31, 2012 (in thousands except for number of projects):
		September 30,			December 31,
		2013			2012
	Balance at beginning of period	$	57,360		$	93,388
	Additions to capitalized exploratory well costs pending the determination of proved reserves		61,751			153,250
	Reclassifications to wells, facilities and equipment based on determination of proved reserves		(80,358	)		(184,298	)
	Capitalized exploratory well costs charged to expense		(3,950	)		
	Divested wells					(4,980	)
	Balance at end of period		34,803			57,360
	Less exploratory well costs that have been capitalized for a period of one year or less		(21,923	)		(45,965	)
	Capitalized exploratory well costs that have been capitalized for a period greater than	$	12,880		$	11,395
	one year
	Number of projects that have exploratory well costs that have been capitalized for a period greater than one year		4			5
Aging of Capitalized Exploratory Well Costs Suspended More Than One Year	The following table provides an aging of capitalized exploratory well costs that have been suspended for more than one year as of September 30, 2013 (in thousands):
		Total			2013			2012		2011		2010		2009		2008
	Capitalized exploratory well costs that have been capitalized for more than one year	$	12,880		$	208		$	6,904	$	1,289	$	72	$	2,884	$	1,523

Indebtness_Tables

Indebtness (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Outstanding	We had the following debt outstanding as of the dates shown below (in thousands) (bank debt interest rate at September 30, 2013 is shown parenthetically; no interest was capitalized during the three months or the nine months ended September 30, 2013 or 2012):
		September 30,		December 31,
		2013		2012
	Bank debt (1.9%)	$	427,000	$	739,000
	Senior subordinated notes:
	7.25% senior subordinated notes due 2018		—		250,000
	8.00% senior subordinated notes due 2019, net of $9,830 and $10,815 discount, respectively		290,170		289,185
	6.75% senior subordinated notes due 2020		500,000		500,000
	5.75% senior subordinated notes due 2021		500,000		500,000
	5.00% senior subordinated notes due 2022		600,000		600,000
	5.00% senior subordinated notes due 2023		750,000		—
	Total debt	$	3,067,170	$	2,878,185

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	9 Months Ended
	Sep. 30, 2013
Asset Retirement Obligations	Our asset retirement obligations primarily represent the estimated present value of the amounts we will incur to plug, abandon and remediate our producing properties at the end of their productive lives. Significant inputs used in determining such obligations include estimates of plugging and abandonment costs, estimated future inflation rates and well life. The inputs are calculated based on historical data as well as current estimated costs. A reconciliation of our liability for plugging and abandonment costs for the nine months ended September 30, 2013 is as follows (in thousands):
		Nine Months
		Ended
		September 30, 2013
	Beginning of period	$	146,478
	Liabilities incurred		5,267
	Liabilities settled		(398	)
	Disposition of wells		(3,104	)
	Accretion expense		8,011
	Change in estimate		(6,231	)
	End of period		150,023
	Less current portion		(2,366	)
	Long-term asset retirement obligations	$	147,657

Capital_Stock_Tables

Capital Stock (Tables)	9 Months Ended
	Sep. 30, 2013
Capital Stock	We have authorized capital stock of 485.0 million shares which includes 475.0 million shares of common stock and 10.0 million shares of preferred stock. We currently have no preferred stock issued or outstanding. The following is a schedule of changes in the number of common shares outstanding since the beginning of 2012:
		Nine Months	Year
		Ended	Ended
		September 30,	December 31,
		2013	2012
	Beginning balance	162,514,098	161,131,547
	Stock options/SARs exercised	257,103	926,425
	Restricted stock granted	401,122	354,674
	Restricted stock units vested	118,324	57,824
	Treasury shares issued	26,497	43,628
	Ending balance	163,317,144	162,514,098

Derivative_ActivitiesTables

Derivative Activities(Tables)	9 Months Ended
	Sep. 30, 2013
Derivative Volumes Hedged and Average Hedge Prices	The following table sets forth our derivative volumes by year as of September 30, 2013:
	Period		Contract Type		Volume Hedged		Weighted
							Average Hedge Price
	Natural Gas
	2013		Collars		280,000 Mmbtu/day		$ 4.59–$ 5.05
	2014		Collars		447,500 Mmbtu/day		$ 3.84–$ 4.48
	2015		Collars		145,000 Mmbtu/day		$ 4.07–$ 4.56
	2013		Swaps		293,370 Mmbtu/day		$	3.82
	2014		Swaps		30,000 Mmbtu/day		$	4.17
	2015		Swaps		7,500 Mmbtu/day		$	4.16
	Crude Oil
	2013		Collars		3,000 bbls/day		$ 90.60–$ 100.00
	2014		Collars		2,000 bbls/day		$ 85.55–$ 100.00
	2013		Swaps		6,825 bbls/day		$	96.79
	2014		Swaps		7,000 bbls/day		$	94.14
	2015		Swaps		2,000 bbls day		$	90.20
	NGLs (Natural Gasoline)
	2013		Sold Swaps		8,000 bbls/day		$	89.64
	2013		Re-purchased Swaps		1,500 bbls/day		$	76.30
	NGLs (Propane)
	2013		Swaps		11,000 bbls/day		$	37.87
	2014		Swaps		7,000 bbls/day		$	40.38
	NGLs (Normal butane)
	2013		Swaps		2,000 bbls/day		$	55.44
	2014		Swaps		2,000 bbls/day		$	54.60
Derivative Fair Value Income	The following table presents information about the components of derivative fair value (loss) income for the three months and the nine months ended September 30, 2013 and 2012 (in thousands):
				Three Months Ended									Nine Months Ended
				September 30,									September 30,
				2013					2012				2013					2012
	Change in fair value of derivatives that did not qualify or were not designated for hedge accounting (a)			$		(34,219	)		$		(53,646	)	$		28,350			$		30,075
	Realized gain (loss) on settlement–natural gas (a) (b)					5,815					—				(17,913	)				—
	Realized (loss) gain on settlement–oil (a) (b)					(8,005	)				1,955				(8,218	)				(1,899	)
	Realized (loss) gain on settlement–NGLs (a) (b)					(3,907	)				14,682				(1,759	)				20,442
	Hedge ineffectiveness		–realized			(854	)				988				(445	)				3,451
			–unrealized			815					(4,707	)			(2,485	)				(5,061	)
	Derivative fair value (loss) income			$		(40,355	)		$		(40,728	)	$		(2,470	)		$		47,008
	(a) Derivatives that did not qualify or were not designated for hedge accounting. Change in fair value of derivatives line also includes gains of $3.1 million in third quarter 2013 and gains of $25.5 million in the first nine months 2013 related to discontinuance of hedge accounting.
	(b) These amounts represent the realized gains and losses on settled derivatives that did not qualify or were not designated for hedge accounting, which before settlement are included in the category in this same table referred to as change in fair value of derivatives that did not qualify or were not designated for hedge accounting.
Schedule of Derivative Off setting Assets and Liabilities Table Text Block	The tables below provide additional information relating to our master netting arrangements with our derivative counterparties (in thousands):
				September 30, 2013
				Gross Amounts of					Gross Amounts				Net Amounts of
				Recognized Assets					Offset in the				Assets Presented in the
									Balance Sheet				Balance Sheet
	Derivative assets:
	Natural gas		–swaps	$		10,965			$		(2,046	)	$		8,919
			–collars			71,699					(1,720	)			69,979
	Crude oil		–swaps			2,962					(7,766	)			(4,804		)
			–collars			137					(1,803	)			(1,666		)
	NGLs		–C5 swaps			3,374					(1,461	)			1,913
			–C3 swaps			7					(552	)			(545		)
			–C4 swaps			406					(135	)			271
				$		89,550			$		(15,483	)	$		74,067
				30-Sep-13
				Gross Amounts of					Gross Amounts				Net Amounts of
				Recognized (Liabilities)					Offset in the				(Liabilities) Presented in the
									Balance Sheet				Balance Sheet
	Derivative (liabilities):
	Natural gas		–swaps	$		(1,219	)		$		2,046		$		827
			–collars			(1,720	)				1,720				—
	Crude oil		–swaps			(7,766	)				7,766				—
			–collars			(1,803	)				1,803				—
	NGLs		–C5 swaps			(9	)				1,461				1,452
			–C3 swaps			(10,469	)				552				(9,917		)
			–C4 swaps			(571	)				135				(436		)
				$		(23,557	)		$		15,483		$		(8,074		)
				December 31, 2012
				Gross Amounts of					Gross Amounts				Net Amounts of
				Recognized Assets					Offset in the				Assets Presented in the
									Balance Sheet				Balance Sheet
	Derivative assets:
	Natural gas		–swaps	$		10,746			$		(3,242	)	$		7,504
			–collars			128,410					(6,155	)			122,255
			–basis swaps			993					—				993
	Crude oil		–swaps			9,650					—				9,650
			–collars			2,222					—				2,222
	NGLs		–C5  swaps			13,055					(2,412	)			10,643
				$		165,076			$		(11,809	)	$		153,267
				31-Dec-12
				Gross Amounts of					Gross Amounts							Net Amounts of
				Recognized (Liabilities)					Offset in the							(Liabilities) Presented in the
									Balance Sheet							Balance Sheet
	Derivative (liabilities):
	Natural gas		–swaps	$		(3,242	)			$		(221	)				$		(3,463		)
			–collars			(9,618	)					9,618							—
	NGLs		–C5 swaps			(137	)					2,412							2,275
			–C3 swaps			(6,746	)					—							(6,746		)
				$		(19,743	)			$		11,809					$		(7,934		)
Fair Value of Derivative Contracts by Consolidated Balance Sheets	The table below provides data about the fair value of our derivative contracts. Derivative assets and liabilities shown below are presented as gross assets and liabilities, without regard to master netting arrangements, which are considered in the presentation of derivative assets and liabilities in the accompanying consolidated balance sheets (in thousands):
		September 30, 2013																December 31, 2012
		Assets					(Liabilities)												Assets					(Liabilities)
		Carrying					Carrying					Net							Carrying					Carrying						Net
		Value					Value					Carrying							Value					Value						Carrying
												Value																		Value
	Derivatives that qualified for cash flow hedge accounting (before discontinuance of hedge accounting):
	Swaps (a)	$		7,091			$		(3,960	)		$	3,131						$		22,236			$		(3,242		)			$		18,994
	Collars (a)			38,685					(10,356	)			28,329								129,878					(9,721		)					120,157
		$		45,776			$		(14,316	)		$	31,460						$		152,114			$		(12,963		)			$		139,151
	Derivatives that did not qualify or were not designated for hedge accounting:
	Sold swaps (a)	$		16,159			$		(23,072	)		$	(6,913		)				$		7,316			$		(8,904		)			$		(1,588	)
	Re-purchased swaps (a)			1,462					—				1,462								5,920					—							5,920
	Collars (a)			42,943					(2,959	)			39,984								857					—							857
	Basis swaps (a)			—					—				—								993					—							993
		$		60,564			$		(26,031	)		$	34,533						$		15,086			$		(8,904		)			$		6,182
	(a) Included in unrealized derivatives in the accompanying consolidated balance sheets. See additional discussion above regarding the discontinuance of hedge accounting.
Effects of Cash Flow Hedges and Other Hedges on Accumulated Other Comprehensive Income	The effects of our cash flow hedges (or those derivatives that previously qualified for hedge accounting) on accumulated other comprehensive income in the accompanying consolidated balance sheets is summarized below (in thousands):
		Three Months Ended September 30,																							Nine Months Ended September 30,
		Change in Hedge										Realized Gain (Loss)											Change in Hedge													Realized Gain (Loss)
		Derivative Fair Value										Reclassified from OCI											Derivative Fair Value													Reclassified from OCI
												into Revenue (a)																								into Revenue (a)
		2013					2012					2013				2012							2013						2012							2013						2012
	Swaps	$		—			$		(33,311	)		$	2,765			$		18,204					$				125		$		22,525			$			14,687			$				69,851
	Put options			—					(994	)			—					(682	)								—				(1,908	)					—							(998	)
	Collars			—					(51,344	)			25,357					43,945									(7,015	)			32,704						83,630							128,823
	Income taxes			—					33,403				(10,967	)				(23,972	)								2,687				(21,780	)					(38,343	)						(76,805	)
		$		—			$		(52,246	)		$	17,155			$		37,495					$				(4,203	)	$		31,541			$			59,974			$				120,871
	(a) For realized gains upon derivative contract settlement, the reduction in AOCI is offset by an increase in revenues, NGLs and oil sales. For realized losses upon derivative contract settlement, the increase in AOCI is offset by a decrease in revenues. See additional discussion above regarding the discontinuance of hedge accounting.
Effects of Non-Hedge Derivatives on Consolidated Statements of Operations	The effects of our non-hedge derivatives (or those derivatives that do not qualify for hedge accounting) and the ineffective portion of our hedge derivatives on our consolidated statements of operations is summarized below (in thousands):
		Three Months Ended September 30,
		Gain (Loss) Recognized in																Gain (Loss) Recognized in																Derivative Fair Value
		Income (Non‑hedge Derivatives)																Income (Ineffective Portion)																Income (Loss)
		2013							2012										2013								2012								2013					2012
	Swaps	$		(48,277		)				$		(45,998		)						$		(39		)				$	(1,556			)				$	(48,316		)		$		(47,554			)
	Re-purchased swaps			1,595								12,822										—							—								1,595						12,822
	Collars			6,366								(1,714		)								—							(2,163			)					6,366						(3,877			)
	Call options			—								(2,119		)								—							—								—						(2,119			)
	Total	$		(40,316		)				$		(37,009		)						$		(39		)				$	(3,719			)				$	(40,355		)		$		(40,728			)
		Nine Months Ended September 30,
		Gain (Loss) Recognized in																Gain (Loss) Recognized in																Derivative Fair Value
		Income (Non‑hedge Derivatives)																Income (Ineffective Portion)																Income (Loss)
		2013							2012										2013								2012								2013					2012
	Swaps	$		(26,350		)				$		30,330								$		(2,034		)				$	(890			)				$	(28,384		)		$		29,440
	Re-purchased swaps			1,117								4,078										—							—								1,117						4,078
	Collars			25,783								3,381										(896		)					(720			)					24,887						2,661
	Call options			—								10,829										—							—								—						10,829
	Basis swaps			(90		)						—																	—								(90		)				—
	Total	$		460						$		48,618								$		(2,930		)				$	(1,610			)				$	(2,470		)		$		47,008

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Hierarchy Table for Assets and Liabilities Measured at Fair Value	We use a market approach for our recurring fair value measurements and endeavor to use the best information available. The following tables present the fair value hierarchy table for assets and liabilities measured at fair value, on a recurring basis (in thousands):
				Fair Value Measurements at September 30, 2013 using:
				Quoted Prices					Significant				Significant					Total
				in Active					Other				Unobservable					Carrying
				Markets for					Observable				Inputs					Value as of
				Identical Assets					Inputs				(Level 3)					September 30,
				(Level 1)					(Level 2)									2013
	Trading securities held in the deferred compensation plans			$		65,663			$		—		$		—			$		65,663
	Derivatives		–swaps			—					(2,320	)			—					(2,320		)
			–collars			—					68,313				—					68,313
				Fair Value Measurements at December 31, 2012 using:
				Quoted Prices									Significant										Significant				Total
				in Active									Other										Unobservable				Carrying
				Markets for									Observable										Inputs				Value as of
				Identical Assets									Inputs										(Level 3)				December 31,
				(Level 1)									(Level 2)														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	We review our long-lived assets to be held and used for impairment including proved natural gas and oil properties, whenever events or circumstances indicate the carrying value of those assets may not be recoverable. In third quarter 2013, we recognized an impairment expense of $7.0 million on certain of our oil and gas properties in South Texas due to reduction in reserves due to a failed well recompletion. Their fair value was measured using an income approach based upon internal estimates of future production levels, drilling and operating costs as well as discount rates, which are Level 3 inputs.  In second quarter 2013, we evaluated certain surface property we own which included consideration of the potential sale of the assets and recognized an impairment charge of $741,000. The following table presents the fair value of these assets at September 30, 2013 measured at fair value on a non-recurring basis (in thousands):
		Three Months Ended																			Nine Months Ended
		September 30,																			September 30,
		2013										2012									2013							2012
				Fair Value					Impairment				Fair Value					Impairment					Fair Value			Impairment			Fair Value			Impairment
	Natural gas and oil properties	$		500			$		7,012			$	—			$		—			$		500	$		7,012	$		—		$	—
	Surface property	$		—			$		—			$	6,269			$		1,281			$		—	$		741	$		6,269		$	1,281
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 September 30, 2013 and December 31, 2012 (in thousands):
		September 30, 2013										December 31, 2012
		Carrying					Fair					Carrying				Fair
		Value					Value					Value				Value
	Assets:
	Commodity swaps and collars	$		74,067			$		74,067			$	153,267			$		153,267
	Marketable securities(a)			65,663					65,663				57,776					57,776
	Liabilities:
	Commodity swaps and collars			(8,074	)				(8,074	)			(7,934	)				(7,934	)
	Bank credit facility(b)			(427,000	)				(427,000	)			(739,000	)				(739,000	)
	Deferred compensation plan(c)			(207,404	)				(204,404	)			(187,604	)				(187,604	)
	7.25% senior subordinated notes due 2018(b)			—					—				(250,000	)				(262,500	)
	8.00% senior subordinated notes due 2019(b)			(290,170	)				(322,125	)			(289,185	)				(332,250	)
	6.75% senior subordinated notes due 2020(b)			(500,000	)				(538,750	)			(500,000	)				(542,500	)
	5.75% senior subordinated notes due 2021(b)			(500,000	)				(525,000	)			(500,000	)				(535,000	)
	5.00% senior subordinated notes due 2022(b)			(600,000	)				(580,500	)			(600,000	)				(627,000	)
	5.00% senior subordinated notes due 2023(b)			(750,000	)				(720,000	)			—					—
	(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 which is a Level 1 market value.

StockBased_Compensation_Plans_

Stock-Based Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2013
Allocation of Stock-Based Compensation by Functional Category	The following table details the allocation of stock-based compensation that is allocated to functional expense categories (in thousands):
		Three Months Ended								Nine Months Ended
		September 30,								September 30,
		2013					2012			2013					2012
	Operating expense	$		699			$		598	$		2,056			$		1,647
	Brokered natural gas and marketing expense			531					452			1,310					1,313
	Exploration expense			983					1,126			3,013					3,048
	General and administrative expense			11,031					10,057			34,600					30,755
	Total	$		13,244			$		12,233	$		40,979			$		36,763
Stock Option and SARs Activities
	We have two active equity-based stock plans, the 2005 Plan and the Director Plan. Under these plans, incentive and non-qualified stock options, SARs, restricted stock units and various other awards may be issued to non-employee directors and employees pursuant to decisions of the Compensation Committee, which is comprised of only non-employee, independent directors. Of the 2.6 million grants outstanding at September 30, 2013, all are grants relating to SARs. Information with respect to SARs activity is summarized below:
		Shares			Weighted
					Average
					Exercise Price
	Outstanding at December 31, 2012	3,433,362			$		52.52
	Granted	470,617					75.82
	Exercised	(1,205,186	)				53.78
	Expired/forfeited	(50,974	)				53.69
	Outstanding at September 30, 2013	2,647,819			$		56.00
Weighted Average Grant Date Fair Value of SARs	During first nine months 2013, we granted SARs to officers and non-officer employees. The weighted average grant date fair value per share of these SARs, based on our Black-Scholes-Merton assumptions, is shown below:
		Nine Months
		Ended
		September 30,
		2013
	Weighted average exercise price per share	$		75.82
	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	$		20.20
Restricted Stock and Restricted Stock Units Outstanding	In first nine months 2013, we granted 406,300 shares of restricted stock Liability Awards as compensation to employees at an average price of $75.45 with vesting generally over a three-year period and 18,300 shares were granted to non-employee directors at an average price of $77.26 with immediate vesting. In the same period of 2012, we granted 365,000 shares of Liability Awards as compensation to employees at an average price of $63.88 with vesting generally over a three-year period and 14,700 shares were granted to non-employee directors at an average price of $64.35 with immediate vesting. We recorded compensation expense for Liability Awards of $16.0 million in first nine months 2013 compared to $15.2 million in the same period of 2012. Substantially all of these awards are held in our deferred compensation plan, are classified as a liability and are remeasured at fair value each reporting period. This mark-to-market adjustment is reported as deferred compensation expense in our consolidated statements of operations (see additional discussion below). A summary of the status of our non-vested restricted stock and restricted stock units outstanding at September 30, 2013 is summarized below:
		Equity Awards										Liability Awards
		Shares				Weighted					Shares					Weighted
						Average Grant										Average Grant
						Date Fair Value										Date Fair Value
	Outstanding at December 31, 2012		349,156			$		59.08					423,478			$		58.91
	Granted		394,053					71.13					424,624					75.53
	Vested		(235,580	)				62.30					(267,621	)				62.07
	Forfeited		(45,589	)				65.32					(21,704	)				57.31
	Outstanding at September 30, 2013		462,040			$		67.11					558,777			$		70.09

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2013
Supplemental Cash Flow Information		Nine Months Ended
		September 30,
		2013			2012
		(in thousands)
	Net cash provided from operating activities included:
	Income taxes (refunded) paid to taxing authorities	$	(237	)	$	436
	Interest paid		129,043			99,828
	Non-cash investing and financing activities included:
	Asset retirement costs (removed) capitalized, net		(964	)		29,695
	Increase in accrued capital expenditures		32,776			6,605

Capitalized_Costs_and_Accumula1

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization (Tables)	9 Months Ended
	Sep. 30, 2013
Capitalized Costs and Accumulated Depreciation, Depletion and Amortization		September 30,			December 31,
		2013			2012
		(in thousands)
	Natural gas and oil properties:
	Properties subject to depletion	$	7,919,627		$	7,368,308
	Unproved properties		748,055			743,467
	Total		8,667,682			8,111,775
	Accumulated depreciation, depletion and amortization		(2,160,378	)		(2,015,591	)
	Net capitalized costs	$	6,507,304		$	6,096,184
	(a) Includes capitalized asset retirement costs and the associated accumulated amortization.

Costs_Incurred_for_Property_Ac1

Costs Incurred for Property Acquisition, Exploration and Development (Tables)	9 Months Ended
	Sep. 30, 2013
Costs Incurred for Property Acquisition, Exploration and Development		Nine			Year
		Months Ended			Ended
		September 30,			December 31,
		2013			2012
		(in thousands)
	Acreage purchases	$	69,987		$	188,843
	Development		727,386			1,049,129
	Exploration:
	Drilling		173,298			309,816
	Expense		47,331			65,758
	Stock-based compensation expense		3,013			4,049
	Gas gathering facilities:
	Development		40,626			41,035
	Subtotal		1,061,641			1,658,630
	Asset retirement obligations		(964	)		57,982
	Total costs incurred	$	1,060,677		$	1,716,612
	(a)              Includes cost incurred whether capitalized or expensed.

Basis_of_Presentation_Addition

Basis of Presentation - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012
Disclosure - Basis of Presentation - Additional Information (Detail) [Line Items]
Retroactive Impact Fee			$24.70
Period related to annual impact fee per well drilled	15 years
Unrealized loss on commodity derivative contracts	$3.10	$25.50

Dispositions_Additional_Inform

Dispositions - Additional Information (Detail) (USD $)

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

6 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Sep. 30, 2013

Feb. 26, 2013

Jun. 30, 2013

Sep. 30, 2013

Sep. 30, 2012

Jun. 30, 2012

Sep. 30, 2012

Mar. 31, 2012

Sep. 30, 2012

West Texas

North Texas

Delaware and Permian Basin

Delaware and Permian Basin

Delaware and Permian Basin

Pennsylvania And West Texas

Pennsylvania And West Texas

Pennsylvania And West Texas

Marcellus Shale

Marcellus Shale

East Texas

East Texas

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Agreed upon sales price of Permian Basin properties

$275,000,000

Gain on sale of equity method investment in a drilling company

4,400,000

Gain (loss) on disposition of oil and gas property

1,700,000

83,500,000

4,000,000

746,000

-2,500,000

-10,900,000

Gain (Loss) on disposition of other assets

-253,000

Selling expenses for property sale

4,200,000

Proceeds from sale of oil and gas

2,600,000

14,200,000

10,000,000

13,900,000

2,500,000

8,600,000

Proceeds from Sale of Other Assets

5,300,000

Proceeds from sale of equity method investment in a drilling company

$7,000,000

Sale of oil and gas properties

75.00%

Overriding royalty in the prospect minimum

1.00%

2.50%

Overriding royalty in the prospect maximum

5.00%

5.00%

Income_Taxes_Income_Tax_Expens

Income Taxes - Income Tax Expense from Continuing Operations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$11,866	($29,074)	$62,180	($17,910)
Effective tax rate	38.20%	35.10%	41.50%	30.90%

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Statutory Tax Rate	35.00%	35.00%	35.00%	35.00%

Income_Loss_Per_Common_Share_C

Income (Loss) Per Common Share - Computations of Basic and Diluted (Loss) Income Per Common Share (Detail) (USD $)	3 Months Ended				9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Net income (loss) per common share:
Net income (loss)	$19,178		($53,836)		$87,551		($39,960)
Participating basic earnings	-341	[1]	-119	[1]	-1,479	[1]	-348	[1]
Basic net income (loss) attributed to common shareholders	18,837		-53,955		86,072		-40,308
Reallocation of participating earnings	1	[1]			6	[1]
Diluted net income (loss) attributed to common shareholders	$18,838		($53,955)		$86,078		($40,308)
Net income (loss) per common share:
Basic	$0.12		($0.34)		$0.54		($0.25)
Diluted	$0.12		($0.34)		$0.53		($0.25)
[1]	Restricted Stock Awards represent participating securities because they participate in nonforfeitable dividends or distributions with common equity owners. Income allocable to participating securities represents the distributed and undistributed earnings attributable to the participating securities. Participating securities, however, do not participate in undistributed net losses.

Income_Loss_Per_Common_Share_B

Income (Loss) Per Common Share - Basic Weighted Average Common Shares Outstanding to Diluted Weighted Average Common Shares Outstanding (Detail)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Denominator:
Basic	160,500	159,563	160,398	159,297
Effect of dilutive securities:
Director and employee stock options and SARs	874		923
Weighted average common shares outstanding – diluted	161,374	159,563	161,321	159,297

Income_Loss_Per_Common_Share_A

Income (Loss) Per Common Share - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net income (loss) per common share:
Weighted Average Number of Shares, Restricted Stock Liability Awards	2,900,000	3,000,000	2,800,000	2,900,000
Stock appreciation rights excluded from earning per share calculation	796		181,000

Suspended_Exploratory_Well_Cos2

Suspended Exploratory Well Costs - Suspended Exploratory Well Costs (Detail) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
	Project	Project
Extractive Industries [Abstract]
Balance at beginning of period	$57,360	$93,388
Additions to capitalized exploratory well costs pending the determination of proved reserves	61,751	153,250
Reclassifications to wells, facilities and equipment based on determination of proved reserves	-80,358	-184,298
Capitalized exploratory well costs charged to expense	-3,950
Divested wells		-4,980
Balance at end of period	34,803	57,360
Less exploratory well costs that have been capitalized for a period of one year or less	-21,923	-45,965
Capitalized exploratory well costs that have been capitalized for a period greater than one year	$12,880	$11,395
Number of projects that have exploratory well costs that have been capitalized for a period greater than one year	4	5

Suspended_Exploratory_Well_Cos3

Suspended Exploratory Well Costs - Aging of Capitalized Exploratory Well Costs Suspended more than One Year (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
In Thousands, unless otherwise specified			Exploratory Well Costs Capitalized In Year Two Thousand And Thirteen	Exploratory Well Costs Capitalized In Year Two Thousand And Twelve	Exploratory Well Costs Capitalized In Year Two Thousand And Eleven	Exploratory Well Costs Capitalized In Year Two Thousand And Ten	Exploratory Well Costs Capitalized In Year Two Thousand And Nine	Exploratory Well Costs Capitalized In Year Two Thousand And Eight
Projects With Exploratory Well Costs Capitalized For More Than One Year [Line Items]
Capitalized exploratory well costs that have been capitalized for more than one year	$12,880	$11,395	$208	$6,904	$1,289	$72	$2,884	$1,523

Suspended_Exploratory_Well_Cos4

Suspended Exploratory Well Costs - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Mar. 31, 2012
In Thousands, unless otherwise specified	Well		East Texas
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Capitalized exploratory well costs that have been capitalized for a period greater than one year	$12,880	$11,395
Number of wells waiting on pipeline	2
Number of wells in completion stage	2
Number of wells not operated	1
Sale of oil and gas properties			75.00%

Indebtedness_Debt_Outstanding_

Indebtedness - Debt Outstanding (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Bank debt	$427,000	$739,000
Subordinated notes	2,640,170	2,139,185
Total debt	3,067,170	2,878,185
7.25% Senior Subordinated notes due 2018
Debt Instrument [Line Items]
Subordinated notes		250,000
8.00% Senior Subordinated notes due 2019
Debt Instrument [Line Items]
Subordinated notes	290,170	289,185
6.75% Senior Subordinated notes due 2020
Debt Instrument [Line Items]
Subordinated notes	500,000	500,000
5.75% Senior Subordinated notes due 2021
Debt Instrument [Line Items]
Subordinated notes	500,000	500,000
5.00% Senior Subordinated notes due 2022
Debt Instrument [Line Items]
Subordinated notes	600,000	600,000
5.00% Senior Subordinated notes due 2023
Debt Instrument [Line Items]
Subordinated notes	$750,000

Indebtedness_Debt_Outstanding_1

Indebtedness - Debt Outstanding (Parenthetical) (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Bank debt percentage	1.90%	1.90%
7.25% Senior Subordinated notes due 2018
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	7.25%	7.25%
8.00% Senior Subordinated notes due 2019
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	8.00%	8.00%
Discount on Senior Subordinated notes	9,830	10,815
6.75% Senior Subordinated notes due 2020
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	6.75%	6.75%
5.75% Senior Subordinated notes due 2021
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	5.75%	5.75%
5.00% Senior Subordinated notes due 2022
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	5.00%	5.00%
5.00% Senior Subordinated notes due 2023
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	5.00%	5.00%

Indebtedness_Additional_Inform

Indebtedness - Additional Information (Detail) (USD $)	3 Months Ended			9 Months Ended		1 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Apr. 30, 2013
						7.25% Senior Subordinated notes due 2018
Debt Instrument [Line Items]
Interest capitalized during the period	$0		$0	$0	$0
Announced call for redemption amount of debt						250,000,000
Loss on early extinguishment of debt		$12,280,000		$12,280,000
Debt redemption price percent of par						103.63%
Ratio of debt to EBITDAX	4.25			4.25
Current ratio	1			1

Indebtedness_Bank_Debt_Additio

Indebtedness - Bank Debt - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended				9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Oct. 18, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
	CommercialBank		CommercialBank			Subsequent Event	Minimum	Maximum	Alternate Base Rate	LIBOR Rate
Debt Instrument [Line Items]
Bank Credit facility, Facility amount	$1,750,000,000		$1,750,000,000			$1,750,000,000
Bank Credit facility, Borrowing base	2,000,000,000		2,000,000,000			2,000,000,000
Percentage holding of commercial banks, Maximum	9.00%		9.00%
Number of commercial banks included in current bank group	28		28
Notice period for increase in facility amount	20 days
Bank debt	427,000,000		427,000,000		739,000,000
Undrawn letters of credit	84,900,000		84,900,000
Borrowing capacity available under the facility amount	$1,200,000,000		$1,200,000,000
Maturity date of loan	18-Feb-16
Minimum range of base rate									0.50%	1.50%
Maximum range of base rate									1.50%	2.50%
Weighted average interest rate on the bank credit facility	1.90%	2.10%	2.00%	2.20%
Annual rate of commitment fee paid on the undrawn balance							0.35%	0.50%
Commitment fee	0.38%
Interest rate margin									0.50%	1.50%

Indebtedness_Senior_Subordinat

Indebtedness - Senior Subordinated Notes - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
5.00% Senior Subordinated notes due 2023
Debt Instrument [Line Items]
Aggregate principal amount of senior subordinated notes	$750,000,000
Interest rate on senior subordinated notes	5.00%	5.00%
Net proceeds from issuance of subordinated notes	738,800,000
Deferred Finance Costs	11,200,000
Aggregate principal amount of senior subordinated notes exchanged	$0
5.00% Senior Subordinated notes due 2023 | Senior note redeemed in March 15, 2018
Debt Instrument [Line Items]
Maximum redemption price of notes as percentage of principal amount	102.50%
5.00% Senior Subordinated notes due 2023 | Senior note redeemed in March 15, 2021
Debt Instrument [Line Items]
Maximum redemption price of notes as percentage of principal amount	100.00%
5.00% Senior Subordinated notes due 2023 | Senior note redeemed in March 15, 2016
Debt Instrument [Line Items]
Maximum redemption price of notes as percentage of principal amount	105.00%
Maximum percentage of original aggregate amount of notes that can be redeemed	35.00%
Minimum percentage of original aggregate principal amount of notes to remain outstanding immediately after redemption	65.00%
Maximum number of days after the date of the closing of the equity offering that the redemption should occur	60 days
Subordinated Debt
Debt Instrument [Line Items]
Purchase price of senior subordinate notes as a percentage of principal	101.00%

Asset_Retirement_Obligations_A

Asset Retirement Obligations - Asset Retirement Obligations (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Asset Retirement Obligation [Abstract]
Beginning of period	$146,478
Liabilities incurred	5,267
Liabilities settled	-398
Disposition of wells	-3,104
Accretion expense	8,011
Change in estimate	-6,231
End of period	150,023
Less current portion	-2,366	-2,470
Long-term asset retirement obligations	$147,657

Capital_Stock_Detail

Capital Stock (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Stockholders' Equity Note [Abstract]
Beginning balance	162,514,098	161,131,547
Stock options/SARs exercised	257,103	926,425
Restricted stock granted	401,122	354,674
Restricted stock units vested	118,324	57,824
Treasury shares issued	26,497	43,628
Ending balance	163,317,144	162,514,098

Capital_Stock_Additional_Infor

Capital Stock - Additional Information (Detail)	Sep. 30, 2013	Dec. 31, 2012
Class Of Stock Disclosures [Abstract]
Authorized capital stock	485,000,000	485,000,000
Common stock, shares authorized	475,000,000	475,000,000
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued
Preferred stock, shares outstanding

Derivative_Activities_Derivati

Derivative Activities - Derivative Volumes Hedged and Average Hedge Prices (Detail)	Sep. 30, 2013
	MMBTU
Collars | Natural Gas 2013
Derivative [Line Items]
Volume Hedged	280,000
Average floor price	4.59
Average cap price	5.05
Collars | Natural Gas 2014
Derivative [Line Items]
Volume Hedged	447,500
Average floor price	3.84
Average cap price	4.48
Collars | Natural Gas 2015
Derivative [Line Items]
Volume Hedged	145,000
Average floor price	4.07
Average cap price	4.56
Collars | Crude Oil 2013
Derivative [Line Items]
Volume Hedged	3,000
Average floor price	90.6
Average cap price	100
Collars | Crude Oil 2014
Derivative [Line Items]
Volume Hedged	2,000
Average floor price	85.55
Average cap price	100
Swaps | Natural Gas 2013
Derivative [Line Items]
Volume Hedged	293,370
Average hedge price	3.82
Swaps | Natural Gas 2014
Derivative [Line Items]
Volume Hedged	30,000
Average hedge price	4.17
Swaps | Natural Gas 2015
Derivative [Line Items]
Volume Hedged	7,500
Average hedge price	4.16
Swaps | Crude Oil 2013
Derivative [Line Items]
Volume Hedged	6,825
Average hedge price	96.79
Swaps | Crude Oil 2014
Derivative [Line Items]
Volume Hedged	7,000
Average hedge price	94.14
Swaps | Crude Oil 2015
Derivative [Line Items]
Volume Hedged	2,000
Average hedge price	90.2
Swaps | NGLs Propane 2013
Derivative [Line Items]
Volume Hedged	11,000
Average hedge price	37.87
Swaps | NGLs Propane 2014
Derivative [Line Items]
Volume Hedged	7,000
Average hedge price	40.38
Swaps | NGLs Butane 2013
Derivative [Line Items]
Volume Hedged	2,000
Average hedge price	55.44
Swaps | NGLs Butane 2014
Derivative [Line Items]
Volume Hedged	2,000
Average hedge price	54.6
Sold Swap | NGLs Natural Gasoline 2013
Derivative [Line Items]
Volume Hedged	8,000
Average hedge price	89.64
Re-purchased Swaps | NGLs Natural Gasoline 2013
Derivative [Line Items]
Volume Hedged	1,500
Average hedge price	76.3

Derivative_Activities_Derivati1

Derivative Activities - Derivative Fair Value Income (Detail) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Derivatives Fair Value [Line Items]
Change in fair value of derivatives that did not qualify or were not designated for hedge accounting	($34,219)	[1]	($53,646)	[1]	$28,350	[1]	$30,075	[1]
Realized gain (loss) on settlement–natural gas	5,815	[1],[2]			-17,913	[1],[2]
Realized (loss) gain on settlement–oil	-8,005	[1],[2]	1,955	[1],[2]	-8,218	[1],[2]	-1,899	[1],[2]
Realized (loss) gain on settlement–NGLs	-3,907	[1],[2]	14,682	[1],[2]	-1,759	[1],[2]	20,442	[1],[2]
Hedge ineffectiveness-realized	-854		988		-445		3,451
Hedge ineffectiveness-unrealized	815		-4,707		-2,485		-5,061
Derivative fair value (loss) income	($40,355)		($40,728)		($2,470)		$47,008
[1]	Derivatives that did not qualify or were not designated for hedge accounting. Change in fair value of derivatives line also includes gains of $3.1 million in third quarter 2013 and gains of $25.5 million in the first nine months 2013 related to discontinuance of hedge accounting.
[2]	These amounts represent the realized gains and losses on settled derivatives that did not qualify or were not designated for hedge accounting, which before settlement are included in the category in this same table referred to as change in fair value of derivatives that did not qualify or were not designated for hedge accounting.

Derivative_Activities_Derivati2

Derivative Activities - Derivative Fair Value Income (Parenthetical) (Detail) (USD $)	3 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013
Disclosure - Derivative Activities - Derivative Fair Value Income (Parenthetical) (Detail) [Line Items]
Derivatives that do not qualify or are not designated for hedge accounting, related to discontinuance of hedge accounting	$3.10	$25.50

Derivative_Activities_Schedule

Derivative Activities - Schedule of Additional Information Related to Master Netting Arrangements with Derivative Counterparties (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivative [Line Items]
Gross Amounts of Recognized Assets	$89,550	$165,076
Gross Amounts Offset in the Balance Sheet	-15,483	-11,809
Net Amounts of Assets Presented in the Balance Sheet	74,067	153,267
Gross Amounts of Recognized (Liabilities)	-23,557	-19,743
Gross Amounts Offset in the Balance Sheet	15,483	11,809
Net Amounts of (Liabilities) Presented in the Balance Sheet	-8,074	-7,934
Natural gas | Swaps
Derivative [Line Items]
Gross Amounts of Recognized Assets	10,965	10,746
Gross Amounts Offset in the Balance Sheet	-2,046	-3,242
Net Amounts of Assets Presented in the Balance Sheet	8,919	7,504
Gross Amounts of Recognized (Liabilities)	-1,219	-3,242
Gross Amounts Offset in the Balance Sheet	2,046	-221
Net Amounts of (Liabilities) Presented in the Balance Sheet	827	-3,463
Natural gas | Collars
Derivative [Line Items]
Gross Amounts of Recognized Assets	71,699	128,410
Gross Amounts Offset in the Balance Sheet	-1,720	-6,155
Net Amounts of Assets Presented in the Balance Sheet	69,979	122,255
Gross Amounts of Recognized (Liabilities)	-1,720	-9,618
Gross Amounts Offset in the Balance Sheet	1,720	9,618
Natural gas | Basis Swap
Derivative [Line Items]
Gross Amounts of Recognized Assets		993
Net Amounts of Assets Presented in the Balance Sheet		993
Crude oil | Swaps
Derivative [Line Items]
Gross Amounts of Recognized Assets	2,962	9,650
Gross Amounts Offset in the Balance Sheet	-7,766
Net Amounts of Assets Presented in the Balance Sheet	-4,804	9,650
Gross Amounts of Recognized (Liabilities)	-7,766
Gross Amounts Offset in the Balance Sheet	7,766
Crude oil | Collars
Derivative [Line Items]
Gross Amounts of Recognized Assets	137	2,222
Gross Amounts Offset in the Balance Sheet	-1,803
Net Amounts of Assets Presented in the Balance Sheet	-1,666	2,222
Gross Amounts of Recognized (Liabilities)	-1,803
Gross Amounts Offset in the Balance Sheet	1,803
Swap NGLs (Natural Gasoline) | C5 swaps
Derivative [Line Items]
Gross Amounts of Recognized Assets	3,374	13,055
Gross Amounts Offset in the Balance Sheet	-1,461	-2,412
Net Amounts of Assets Presented in the Balance Sheet	1,913	10,643
Gross Amounts of Recognized (Liabilities)	-9	-137
Gross Amounts Offset in the Balance Sheet	1,461	2,412
Net Amounts of (Liabilities) Presented in the Balance Sheet	1,452	2,275
Swap NGLs (Natural Gasoline) | C3 swaps
Derivative [Line Items]
Gross Amounts of Recognized Assets	7
Gross Amounts Offset in the Balance Sheet	-552
Net Amounts of Assets Presented in the Balance Sheet	-545
Gross Amounts of Recognized (Liabilities)	-10,469	-6,746
Gross Amounts Offset in the Balance Sheet	552
Net Amounts of (Liabilities) Presented in the Balance Sheet	-9,917	-6,746
Swap NGLs (Natural Gasoline) | C4 swaps
Derivative [Line Items]
Gross Amounts of Recognized Assets	406
Gross Amounts Offset in the Balance Sheet	-135
Net Amounts of Assets Presented in the Balance Sheet	271
Gross Amounts of Recognized (Liabilities)	-571
Gross Amounts Offset in the Balance Sheet	135
Net Amounts of (Liabilities) Presented in the Balance Sheet	($436)

Derivative_Activities_Fair_Val

Derivative Activities - Fair Value of Derivative Contracts, by Consolidated Balance Sheets (Detail) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Derivatives Fair Value [Line Items]
Assets Carrying Value	$45,776		$152,114
Liabilities Carrying Value	-14,316		-12,963
Net Carrying Value	31,460		139,151
Assets Carrying Value	60,564		15,086
Liabilities Carrying Value	-26,031		-8,904
Net Carrying Value	34,533		6,182
Swaps
Derivatives Fair Value [Line Items]
Assets Carrying Value	7,091	[1]	22,236	[1]
Liabilities Carrying Value	-3,960	[1]	-3,242	[1]
Net Carrying Value	3,131	[1]	18,994	[1]
Collars
Derivatives Fair Value [Line Items]
Assets Carrying Value	38,685	[1]	129,878	[1]
Liabilities Carrying Value	-10,356	[1]	-9,721	[1]
Net Carrying Value	28,329	[1]	120,157	[1]
Assets Carrying Value	42,943	[1]	857	[1]
Liabilities Carrying Value	-2,959	[1]
Net Carrying Value	39,984	[1]	857	[1]
Sold Swap
Derivatives Fair Value [Line Items]
Assets Carrying Value	16,159	[1]	7,316	[1]
Liabilities Carrying Value	-23,072	[1]	-8,904	[1]
Net Carrying Value	-6,913	[1]	-1,588	[1]
Re-purchased swaps
Derivatives Fair Value [Line Items]
Assets Carrying Value	1,462	[1]	5,920	[1]
Net Carrying Value	1,462	[1]	5,920	[1]
Basis Swap
Derivatives Fair Value [Line Items]
Assets Carrying Value			993	[1]
Net Carrying Value			$993	[1]
[1]	Included in unrealized derivatives in the accompanying consolidated balance sheets. See additional discussion above regarding the discontinuance of hedge accounting.

Derivative_Activities_Effects_

Derivative Activities - Effects of Cash Flow Hedges and Other Hedges on Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended				9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Derivative Instruments Gain Loss [Line Items]
Change in unrealized deferred hedging gains, tax effect			$33,403		$2,687		($21,780)
Change in unrealized deferred hedging (losses) gains, net of taxes			-52,246	[1]	-4,203	[1]	31,541	[1]
Realized gain (loss) reclassified from AOCI into revenue, income taxes	-10,967	[2]	-23,972	[2]	-38,343	[2]	-76,805	[2]
Realized gain on hedge derivative contract settlements reclassified into earnings from other comprehensive income, net of taxes	17,155	[2]	37,495	[2]	59,974	[2]	120,871	[2]
Swaps
Derivative Instruments Gain Loss [Line Items]
Change in Hedge Derivative Fair Value			-33,311		125		22,525
Realized Gain (Loss) Reclassified from OCI into Revenue	2,765	[2]	18,204	[2]	14,687	[2]	69,851	[2]
Put Option
Derivative Instruments Gain Loss [Line Items]
Change in Hedge Derivative Fair Value			-994				-1,908
Realized Gain (Loss) Reclassified from OCI into Revenue			-682	[2]			-998	[2]
Collars
Derivative Instruments Gain Loss [Line Items]
Change in Hedge Derivative Fair Value			-51,344		-7,015		32,704
Realized Gain (Loss) Reclassified from OCI into Revenue	$25,357	[2]	$43,945	[2]	$83,630	[2]	$128,823	[2]
[1]	Amounts are net of income tax expense of $33,403 for the three months ended September 30, 2012 and income tax benefit of $21,780 for the nine months ended September 30, 2012. Amounts are net of income tax expense of $2,687 for the nine months ended September 30, 2013.
[2]	For realized gains upon derivative contract settlement, the reduction in AOCI is offset by an increase in revenues, NGLs and oil sales. For realized losses upon derivative contract settlement, the increase in AOCI is offset by a decrease in revenues. See additional discussion above regarding the discontinuance of hedge accounting.

Derivative_Activities_Effects_1

Derivative Activities - Effects of Non-Hedge Derivatives on Consolidated Statement of Operations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Recognized in Income (Non-hedge Derivatives)	($40,316)	($37,009)	$460	$48,618
Gain (Loss) Recognized in Income (Ineffective Portion)	-39	-3,719	-2,930	-1,610
Derivative Fair Value Income (Loss)	-40,355	-40,728	-2,470	47,008
Swaps
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Recognized in Income (Non-hedge Derivatives)	-48,277	-45,998	-26,350	30,330
Gain (Loss) Recognized in Income (Ineffective Portion)	-39	-1,556	-2,034	-890
Derivative Fair Value Income (Loss)	-48,316	-47,554	-28,384	29,440
Re-purchased swaps
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Recognized in Income (Non-hedge Derivatives)	1,595	12,822	1,117	4,078
Derivative Fair Value Income (Loss)	1,595	12,822	1,117	4,078
Collars
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Recognized in Income (Non-hedge Derivatives)	6,366	-1,714	25,783	3,381
Gain (Loss) Recognized in Income (Ineffective Portion)		-2,163	-896	-720
Derivative Fair Value Income (Loss)	6,366	-3,877	24,887	2,661
Call Option
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Recognized in Income (Non-hedge Derivatives)		-2,119		10,829
Derivative Fair Value Income (Loss)		-2,119		10,829
Basis Swap
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Recognized in Income (Non-hedge Derivatives)			-90
Derivative Fair Value Income (Loss)			($90)

Derivative_Activities_Addition

Derivative Activities - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended	12 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
					2013	2013	Designated as Hedging Instrument	Designated as Hedging Instrument	Designated as Hedging Instrument	Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets liabilities at fair value net	$66,000,000		$66,000,000
Unrealized pre-tax derivative gain recorded in AOCI			32,300,000
Unrealized after tax derivative gain recorded in AOCI			19,700,000
Gains (Losses) in oil and gas sales related to settled hedging transactions							27,400,000	61,500,000	94,400,000	197,700,000
Ineffective unrealized and realized gains (losses) recognized income	39,000	3,719,000	2,930,000	1,610,000
Unrealized net gains, reclassify into earnings			3,900,000
Accumulated other comprehensive income, unrealized net gains			103,600,000
Accumulated other comprehensive income, unrealized net gains, after tax			63,200,000
Unrealized pre-tax derivative gain expected to be reclassified into earnings					$22,100,000	$10,200,000

Fair_Value_Measurements_Fair_V

Fair Value Measurements - Fair Value Hierarchy Table for Assets and Liabilities Measured at Fair Value (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net	$66,000
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities held in the deferred compensation plans	65,663	57,776
Fair Value, Measurements, Recurring | Swaps
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net	-2,320	23,326
Fair Value, Measurements, Recurring | Collars
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net	68,313	121,014
Fair Value, Measurements, Recurring | Basis Swap
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net		993
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities held in the deferred compensation plans	65,663	57,776
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Swaps
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Collars
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Basis Swap
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities held in the deferred compensation plans
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Swaps
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net	-2,320	23,326
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Collars
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net	68,313	121,014
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Basis Swap
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net		993
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Trading securities held in the deferred compensation plans
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Swaps
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Collars
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Basis Swap
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets liabilities at fair value net

Fair_Value_Measurements_Carryi

Fair Value Measurements - Carrying Amounts and Fair Values of Financial Instruments (Detail) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Assets
Commodity swaps and collars	$74,067		$153,267
Liabilities
Commodity swaps and collars	8,074		7,934
Bank credit facility	-427,000		-739,000
Deferred compensation plan	-207,404		-187,604
Subordinated debt	-2,640,170		-2,139,185
Carrying Value
Assets
Commodity swaps and collars	74,067		153,267
Marketable securities	65,663	[1]	57,776	[1]
Liabilities
Commodity swaps and collars	-8,074		-7,934
Bank credit facility	-427,000	[2]	-739,000	[2]
Deferred compensation plan	-207,404	[3]	-187,604	[3]
Fair Value
Assets
Commodity swaps and collars	74,067		153,267
Marketable securities	65,663	[1]	57,776	[1]
Liabilities
Commodity swaps and collars	-8,074		-7,934
Bank credit facility	-427,000	[2]	-739,000	[2]
Deferred compensation plan	-204,404	[3]	-187,604	[3]
7.25% Senior Subordinated notes due 2018
Liabilities
Subordinated debt			-250,000
7.25% Senior Subordinated notes due 2018 | Carrying Value
Liabilities
Subordinated debt			-250,000	[2]
7.25% Senior Subordinated notes due 2018 | Fair Value
Liabilities
Subordinated debt			-262,500	[2]
8.00% Senior Subordinated notes due 2019
Liabilities
Subordinated debt	-290,170		-289,185
8.00% Senior Subordinated notes due 2019 | Carrying Value
Liabilities
Subordinated debt	-290,170	[2]	-289,185	[2]
8.00% Senior Subordinated notes due 2019 | Fair Value
Liabilities
Subordinated debt	-322,125	[2]	-332,250	[2]
6.75% Senior Subordinated notes due 2020
Liabilities
Subordinated debt	-500,000		-500,000
6.75% Senior Subordinated notes due 2020 | Carrying Value
Liabilities
Subordinated debt	-500,000	[2]	-500,000	[2]
6.75% Senior Subordinated notes due 2020 | Fair Value
Liabilities
Subordinated debt	-538,750	[2]	-542,500	[2]
5.75% Senior Subordinated Notes due 2021 | Carrying Value
Liabilities
Subordinated debt	-500,000	[2]	-500,000	[2]
5.75% Senior Subordinated Notes due 2021 | Fair Value
Liabilities
Subordinated debt	-525,000	[2]	-535,000	[2]
5.00% Senior Subordinated notes due 2022
Liabilities
Subordinated debt	-600,000		-600,000
5.00% Senior Subordinated notes due 2022 | Carrying Value
Liabilities
Subordinated debt	-600,000	[2]	-600,000	[2]
5.00% Senior Subordinated notes due 2022 | Fair Value
Liabilities
Subordinated debt	-580,500	[2]	-627,000	[2]
5.00% senior subordinated notes due 2023 | Carrying Value
Liabilities
Subordinated debt	-750,000	[2]
5.00% senior subordinated notes due 2023 | Fair Value
Liabilities
Subordinated debt	($720,000)	[2]
[1]	Marketable securities, which are held in our deferred compensation plans, are actively traded on major exchanges. Refer to Note 13 for additional information.
[2]	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.
[3]	The fair value of our deferred compensation plan is updated on the closing price on the balance sheet date which is a Level 1 market value.

Fair_Value_Measurements_Carryi1

Fair Value Measurements - Carrying Amounts and Fair Values of Financial Instruments (Parenthetical) (Detail)	Sep. 30, 2013	Dec. 31, 2012
7.25% Senior Subordinated notes due 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate on senior subordinated notes	7.25%	7.25%
8.00% Senior Subordinated notes due 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate on senior subordinated notes	8.00%	8.00%
6.75% Senior Subordinated notes due 2020
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate on senior subordinated notes	6.75%	6.75%
5.75% Senior Subordinated Notes due 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate on senior subordinated notes	5.75%	5.75%
5.00% Senior Subordinated notes due 2022
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate on senior subordinated notes	5.00%	5.00%
5.00% senior subordinated notes due 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate on senior subordinated notes	5.00%	5.00%

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
			Company
			Lenders
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest and dividends	$111,000	$122,000	$779,000	$279,000
Mark-to-market gain (loss)	3,200,000	3,800,000	3,800,000	5,700,000
Allowance for uncollectible receivables	2,500,000		2,500,000		2,400,000
Number of financial institutions included in counter parties			15
Number of secured lenders not in banking credit facility			2
Net derivative asset	53,000		53,000
Impairment of proved properties and other assets	7,012,000	1,281,000	7,753,000	1,281,000
Surface Property | Fair Value, Measurements, Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment of proved properties and other assets		1,281,000	741,000	1,281,000
Natural Gas and Oil Properties | Fair Value, Measurements, Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment of proved properties and other assets	$7,012,000		$7,012,000

Fair_Value_Measurements_Value_

Fair Value Measurements - Value of Assets Measured at Fair Value on Non Recurring Basis (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment	$7,012	$1,281	$7,753	$1,281
Fair Value, Measurements, Nonrecurring | Natural Gas and Oil Properties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value	500		500
Impairment	7,012		7,012
Fair Value, Measurements, Nonrecurring | Surface Property
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair Value		6,269		6,269
Impairment		$1,281	$741	$1,281

StockBased_Compensation_Plans_1

Stock-Based Compensation Plans - Allocation of Stock-Based Compensation by Functional Category (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$13,244	$12,233	$40,979	$36,763
Operating Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	699	598	2,056	1,647
Brokered Natural Gas and Marketing Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	531	452	1,310	1,313
Exploration Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	983	1,126	3,013	3,048
General and Administrative Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total	$11,031	$10,057	$34,600	$30,755

StockBased_Compensation_Plans_2

Stock-Based Compensation Plans - SARs Activity (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Schedule Of Stock Option Activity [Line Items]
Beginning Balance, Shares	3,433,362
Granted, Shares	470,617
Exercised, Shares	-1,205,186
Expired/forfeited, Shares	-50,974
Ending Balance, Shares	2,647,819
Beginning Balance, Weighted Average Exercise Price	$52.52
Granted, Weighted Average Exercise Price	$75.82
Exercised, Weighted Average Exercise Price	$53.78
Expired/forfeited, Weighted Average Exercise Price	$53.69
Ending Balance, Weighted Average Exercise Price	$56

StockBased_Compensation_Plans_3

Stock-Based Compensation Plans - Weighted Average Grant Date Fair Value of SARs (Detail) (Stock Appreciation Rights (SARs), USD $)	9 Months Ended
	Sep. 30, 2013
Stock Appreciation Rights (SARs)
Schedule Of Weighted Average Assumptions For Fair Values Of Stock Options [Line Items]
Weighted average exercise price per share	$75.82
Expected annual dividends per share	0.21%
Expected life in years	3 years 8 months 12 days
Expected volatility	35.00%
Risk-free interest rate	0.60%
Weighted average grant date fair value per share	$20.20

StockBased_Compensation_Plans_4

Stock-Based Compensation Plans - Restricted Stock and Restricted Stock Units Outstanding (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Equity Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding, Beginning Balance	349,156
Granted	394,053
Vested	-235,580
Forfeited	-45,589
Outstanding, Ending Balance	462,040
Outstanding, Beginning Balance	$59.08
Granted	$71.13
Vested	$62.30
Forfeited	$65.32
Outstanding, Ending Balance	$67.11
Liability Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding, Beginning Balance	423,478
Granted	424,624
Vested	-267,621
Forfeited	-21,704
Outstanding, Ending Balance	558,777
Outstanding, Beginning Balance	$58.91
Granted	$75.53
Vested	$62.07
Forfeited	$57.31
Outstanding, Ending Balance	$70.09

StockBased_Compensation_Plans_5

Stock-Based Compensation Plans - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
			Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			3 years
Expiration term of stock options			5 years
Active equity-based stock plans			2
Stock-based compensation expense	$13,244,000	$12,233,000	$40,979,000	$36,763,000
Non-cash, Mark-to-market income (loss) related to deferred compensation plan	2,200,000	-20,100,000	-33,300,000	-21,600,000
Shares held in rabbi trust total	2,900,000		2,900,000		2,700,000
Vested shares held in rabbi trust	2,300,000		2,300,000		2,300,000
Equity Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted to employees			394,100	359,700
Granted			$71.13	$63.37
Stock-based compensation expense			14,600,000	8,200,000
Vesting period of shares granted to employees			three-year	three-year
Liability Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense			$16,000,000	$15,200,000
Vesting period of shares granted to employees			three-year	three-year
Liability Awards | Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted			$75.45	$63.88
Shares granted			406,300	365,000
Liability Awards | Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted			$77.26	$64.35
Shares granted			18,300	14,700
Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of stock option outstanding	2,600,000		2,600,000

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information - Supplemental Cash Flow Information (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Net cash provided from operating activities included:
Income taxes (refunded) paid to taxing authorities	($237)	$436
Interest paid	129,043	99,828
Non-cash investing and financing activities included:
Asset retirement costs (removed) capitalized, net	-964	29,695
Increase in accrued capital expenditures	$32,776	$6,605

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Commitments And Contingencies Disclosure [Line Items]
Legal Settlement for Drummond Lawsuit	$87.50
Transportation commitments future minimum transportation fees due nine months change	$150
Number of years transportation commitments future minimum transportation fees due nine months change	10 years

Capitalized_Costs_and_Accumula2

Capitalized Costs and Accumulated Depreciation, Depletion and Amortization - Capitalized Costs and Accumulated Depreciation, Depletion and Amortization (Detail) (USD $)	Sep. 30, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Natural gas and oil properties:
Properties subject to depletion	$7,919,627	[1]	$7,368,308	[1]
Unproved properties	748,055	[1]	743,467	[1]
Total	8,667,682	[1]	8,111,775	[1]
Accumulated depreciation, depletion and amortization	-2,160,378	[1]	-2,015,591	[1]
Net capitalized costs	$6,507,304	[1]	$6,096,184	[1]
[1]	Includes capitalized asset retirement costs and the associated accumulated amortization

Costs_Incurred_for_Property_Ac2

Costs Incurred for Property Acquisition, Exploration and Development - Costs Incurred for Property Acquisition, Exploration and Development (Detail) (USD $)	3 Months Ended		9 Months Ended			12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012	Dec. 31, 2012
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items]
Acreage purchases			$69,987	[1]		$188,843	[1]
Development			727,386	[1]		1,049,129	[1]
Exploration:
Drilling			173,298	[1]		309,816	[1]
Expense			47,331	[1]		65,758	[1]
Stock-based compensation expense	13,244	12,233	40,979		36,763
Gas gathering facilities:
Development			40,626	[1]		41,035	[1]
Subtotal			1,061,641	[1]		1,658,630	[1]
Asset retirement obligations			-964	[1]		57,982	[1]
Total costs incurred			1,060,677	[1]		1,716,612	[1]
Exploration Expense
Exploration:
Stock-based compensation expense			$3,013	[1]		$4,049	[1]
[1]	Includes cost incurred whether capitalized or expensed.