Concho Resources (CXO) 10-Q 12 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	8-May-14
Document Documentand Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'CXO	'
Entity Registrant Name	'CONCHO RESOURCES INC	'
Entity Central Index Key	'0001358071	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	105,227,041

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$21	$21
Accounts receivable, net of allowance for doubtful accounts:	'	'
Oil and natural gas	266,489	223,790
Joint operations and other	249,568	247,945
Derivative instruments	1,358	590
Deferred income taxes	40,039	30,069
Prepaid costs and other	17,956	18,460
Total current assets	575,431	520,875
Property and equipment:	'	'
Oil and natural gas properties, successful efforts method	11,768,415	11,215,373
Accumulated depletion and depreciation	-2,600,913	-2,384,108
Total oil and natural gas properties, net	9,167,502	8,831,265
Other property and equipment, net	116,159	114,783
Total property and equipment, net	9,283,661	8,946,048
Deferred loan costs, net	69,701	73,048
Intangible asset - operating rights, net	28,250	28,615
Inventory	18,674	19,682
Noncurrent derivative instruments	269	966
Other assets	2,182	1,930
Total assets	9,978,168	9,591,164
Accounts payable:	'	'
Trade	34,071	13,936
Bank overdrafts	90,285	36,718
Revenue payable	199,292	177,617
Accrued and prepaid drilling costs	372,896	318,296
Derivative instruments	70,824	53,701
Other current liabilities	171,236	156,600
Total current liabilities	938,604	756,868
Long-term debt	3,674,434	3,630,421
Deferred income taxes	1,386,577	1,334,653
Noncurrent derivative instruments	17,814	14,088
Asset retirement obligations and other long-term liabilities	99,552	97,185
Commitments and contingencies (Note I)	'	'
Stockholders' equity:	'	'
Common stock, $0.001 par value; 300,000,000 authorized; 105,397,895 and 105,222,765 shares issued at March 31, 2014 and December 31, 2013, respectively	105	105
Additional paid-in capital	2,042,841	2,027,162
Retained earnings	1,832,873	1,741,566
Treasury stock, at cost; 160,597 and 127,305 shares at March 31, 2014 and December 31, 2013, respectively	-14,632	-10,884
Total stockholders' equity	3,861,187	3,757,949
Total liabilities and stockholders' equity	$9,978,168	$9,591,164

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]	'	'
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	105,397,895	105,222,765
Treasury shares	160,597	127,305

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating revenues:	'	'
Oil sales	$539,857	$393,208
Natural gas sales	121,102	78,919
Total operating revenues	660,959	472,127
Operating costs and expenses:	'	'
Oil and natural gas production	126,924	100,845
Exploration and abandonments	25,375	18,407
Depreciation, depletion and amortization	221,392	168,420
Accretion of discount on asset retirement obligations	1,671	1,394
General and administrative (including non-cash stock-based compensation of $11,432 and $6,767 for the three months ended March 31, 2014 and 2013, respectively)	47,750	43,293
Loss on derivatives not designated as hedges	35,615	59,017
Total operating costs and expenses	458,727	391,376
Income (loss) from continuing operations	202,232	80,751
Other income (expense):	'	'
Interest expense	-56,135	-52,106
Other, net	541	-109
Total other expense	-55,594	-52,215
Income before income taxes	146,638	28,536
Income tax expense	-55,331	-10,977
Income from continuing operations	91,307	17,559
Income from discontinued operations, net of tax	0	12,534
Net income	$91,307	$30,093
Basic earnings per share:	'	'
Income from continuing operations	$0.87	$0.17
Income from discontinued operations, net of tax	$0	$0.12
Net income	$0.87	$0.29
Diluted earnings per share:	'	'
Income from continuing operations	$0.87	$0.17
Income from discontinued operations, net of tax	$0	$0.12
Net income	$0.87	$0.29

Consolidated_Statements_of_Ope1

Consolidated Statements of Operations (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]	'	'
Non-cash stock-based compensation	$11,432	$6,767

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders Equity (USD $)	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]
In Thousands, except Share data
BALANCE at Dec. 31, 2013	$3,757,949	$105	$2,027,162	$1,741,566	($10,884)
BALANCE, Shares at Dec. 31, 2013	'	105,223,000	'	'	127,000
Net income	91,307	0	0	91,307	0
Stock options exercised	1,254	0	1,254	0	0
Stock options exercised, shares	60,676	61,000	'	'	0
Grants of restricted stock, shares	134,989	135,000	'	'	0
Cancellation of restricted stock, shares	'	-21,000	'	'	0
Stock-based compensation	11,432	0	11,432	0	0
Excess tax benefits related to stock-based compensation	2,993	0	2,993	0	0
Purchase of treasury stock	-3,748	0	0	0	-3,748
Purchase of treasury stock, shares	'	0	'	'	34,000
BALANCE at Mar. 31, 2014	$3,861,187	$105	$2,042,841	$1,832,873	($14,632)
BALANCE, Shares at Mar. 31, 2014	'	105,398,000	'	'	161,000

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'
Net income	$91,307	$30,093
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation, depletion and amortization	221,392	168,420
Accretion of discount on asset retirement obligations	1,671	1,394
Exploration and abandonments, including dry holes	23,759	4,478
Non-cash compensation expense	11,432	6,767
Deferred income taxes	41,954	11,500
(Gain) loss on disposition of assets, net	-146	5
Loss on derivatives not designated as hedges	35,615	59,017
Discontinued operations	0	-19,754
Other non-cash items	2,710	3,376
Changes in operating assets and liabilities, net of acquisitions:	'	'
Accounts receivable	-10,139	12,608
Prepaid costs and other	21	726
Inventory	1,126	-21
Accounts payable	20,087	-27,679
Revenue payable	21,675	-15,636
Other current liabilities	13,516	-15,623
Net cash provided by operating activities	475,980	219,671
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'
Capital expenditures on oil and natural gas properties	-554,266	-419,766
Additions to other property and equipment	-5,617	-4,244
Proceeds from the disposition of assets	24	15,865
Settlements received from (paid on) derivatives not designated as hedges	-14,837	6,016
Net cash used in investing activities	-574,696	-402,129
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'
Proceeds from issuance of debt	593,400	626,700
Payments of debt	-548,750	-463,300
Exercise of stock options	1,254	2,059
Excess tax benefit from stock-based compensation	2,993	3,277
Purchase of treasury stock	-3,748	-2,909
Bank overdrafts	53,567	14,725
Net cash provided by financing activities	98,716	180,552
Net increase (decrease) in cash and cash equivalents	0	-1,906
Cash and cash equivalents at beginning of period	21	2,880
Cash and cash equivalents at end of period	$21	$974

Organization_and_nature_of_ope

Organization and nature of operations	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization and nature of operations	'
	Note A. Organization and nature of operations
	Concho Resources Inc. (the “Company”) is a Delaware corporation formed on February 22, 2006. The Company's principal business is the acquisition, development and exploration of oil and natural gas properties primarily located in the Permian Basin region of Southeast New Mexico and West Texas.

Summary_of_significant_account

Summary of significant accounting policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Summary of significant accounting policies	'
	Note B. Summary of significant accounting policies
	Principles of consolidation. The consolidated financial statements of the Company include the accounts of the Company and its wholly-owned subsidiaries. The Company consolidates the financial statements of these entities. All material intercompany balances and transactions have been eliminated.
	Use of estimates in the preparation of financial statements.  Preparation of financial statements in conformity with generally accepted accounting principles in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from these estimates. Depletion of oil and natural gas properties is determined using estimates of proved oil and natural gas reserves. There are numerous uncertainties inherent in the estimation of quantities of proved reserves and in the projection of future rates of production and the timing of development expenditures. Similarly, evaluations for impairment of proved and unproved oil and natural gas properties are subject to numerous uncertainties including, among others, estimates of future recoverable reserves and commodity price outlooks. Other significant estimates include, but are not limited to, the asset retirement obligations, fair value of derivative financial instruments, the fair value of business combinations, fair value of stock-based compensation and income taxes.
	Interim financial statements. The accompanying consolidated financial statements of the Company have not been audited by the Company's independent registered public accounting firm, except that the consolidated balance sheet at December 31, 2013 is derived from audited consolidated financial statements. In the opinion of management, the accompanying consolidated financial statements reflect all adjustments necessary to present fairly the Company's consolidated financial statements. All such adjustments are of a normal, recurring nature. In preparing the accompanying consolidated financial statements, management has made certain estimates and assumptions that affect reported amounts in the consolidated financial statements and disclosures of contingencies. Actual results may differ from those estimates. The results for interim periods are not necessarily indicative of annual results.
	Certain disclosures have been condensed in or omitted from these consolidated financial statements. Accordingly, these condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2013.
	Deferred loan costs. Deferred loan costs are stated at cost, net of amortization, which is computed using the effective interest and straight-line methods. The Company had deferred loan costs of $69.7 million and $73.0 million, net of accumulated amortization of $52.1 million and $48.7 million, at March 31, 2014 and December 31, 2013, respectively.
	The following table reflects the future amortization expense of deferred loan costs at March 31, 2014:
	(in thousands)
	Remaining 2014		$	10,156
	2015			13,820
	2016			8,476
	2017			5,994
	2018			6,376
	2019			6,784
	Thereafter			18,095
		Total	$	69,701
	Intangible assets. The Company has capitalized certain operating rights acquired in an acquisition. The gross operating rights, which have no residual value, are amortized over the estimated economic life of 25 years. Impairment will be assessed if indicators of potential impairment exist or when there is a material change in the remaining useful economic life. The following table reflects the gross and net intangible assets at March 31, 2014 and December 31, 2013:
				March 31,		December 31,
	(in thousands)			2014		2013
	Gross intangible - operating rights		$	36,557	$	36,557
	Accumulated amortization			-8,307		-7,942
		Net intangible - operating rights	$	28,250	$	28,615
	The following table reflects amortization expense for the three months ended March 31, 2014 and 2013:
			Three Months Ended
			March 31,
	(in thousands)		2014		2013
	Amortization expense		$	365	$	365
	The following table reflects the estimated aggregate amortization expense for each of the periods presented below at March 31, 2014:
	(in thousands)
	Remaining 2014		$	1,096
	2015			1,461
	2016			1,461
	2017			1,461
	2018			1,461
	2019			1,461
	Thereafter			19,849
		Total	$	28,250
	Revenue recognition. Oil and natural gas revenues are recorded at the time of physical transfer of such products to the purchaser, which for the Company is primarily at the wellhead. The Company follows the sales method of accounting for oil and natural gas sales, recognizing revenues based on the Company's share of actual proceeds from the oil and natural gas sold to purchasers.
	General and administrative expense. The Company receives fees for the operation of jointly-owned oil and natural gas properties and records such reimbursements as reductions of general and administrative expense. Such fees totaled approximately $5.1 million and $4.2 million for the three months ended March 31, 2014 and 2013, respectively.
	Recent accounting pronouncements. In April 2014, the Financial Accounting Standards Board issued guidance that raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. Under the revised standard, a discontinued operation is (i) a component of an entity or group of components that has been disposed of by sale, disposed of other than by sale or is classified as held for sale that represents a strategic shift that has or will have a major effect on an entity's operations and financial results or (ii) an acquired business or nonprofit activity that is classified as held for sale on the date of the acquisition. This update is aimed at reducing the frequency of disposals reported as discontinued operations by focusing on strategic shifts that have or will have a major effect on an entity's operations and financial results.
	An entity is required to apply this guidance for annual reporting periods beginning on or after December 15, 2014, and interim periods within those annual periods, though earlier adoption is permitted. An entity should provide the disclosures required by this amendment prospectively. The Company is evaluating the impact of this new guidance and does not expect it to have a significant impact on the consolidated financial statements.

Exploratory_well_costs

Exploratory well costs	3 Months Ended
	Mar. 31, 2014
Disclosure Exploratory Well Costs Capitalized Exploratory Well Activity [Abstract]	'
Exploratory well costs	'
	Note C. Exploratory well costs
	The Company capitalizes exploratory well costs until a determination is made that the well has either found proved reserves or that it is impaired. After an exploratory well has been completed and found oil and natural gas reserves, a determination may be pending as to whether the oil and natural reserves can be classified as proved. In those circumstances, the Company continues to capitalize the well or project costs pending the determination of proved status if (i) the well has found a sufficient quantity of reserves to justify its completion as a producing well and (ii) the Company is making sufficient progress assessing the reserves and the economic and operating viability of the project. The capitalized exploratory well costs are carried in unproved oil and natural gas properties. See Note Q for the proved and unproved components of oil and natural gas properties. If the exploratory well is determined to be impaired, the well costs are charged to exploration and abandonments expense in the consolidated statements of operations.
	The following table reflects the Company's net capitalized exploratory well activity during the three months ended March 31, 2014:
			Three Months Ended
	(in thousands)		31-Mar-14
	Beginning capitalized exploratory well costs			$	144,504
		Additions to exploratory well costs pending the determination of proved reserves			134,660
		Reclassifications due to determination of proved reserves			-86,904
		Exploratory well costs charged to expense			-19,286
	Ending capitalized exploratory well costs			$	172,974
	The following table provides an aging at March 31, 2014 and December 31, 2013 of capitalized exploratory well costs based on the date drilling was completed:
					March 31,		December 31,
	(dollars in thousands)				2014		2013
	Capitalized exploratory well costs that have been capitalized for a period of one year or less			$	152,891	$	122,753
	Capitalized exploratory well costs that have been capitalized for a period greater than one year				20,083		21,751
		Total capitalized exploratory well costs		$	172,974	$	144,504
	Number of projects with exploratory well costs that have been capitalized for a period greater
		than one year			12		10
	Southern Delaware Basin projects. At March 31, 2014,

Asset_retirement_obligations

Asset retirement obligations	3 Months Ended
	Mar. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]	'
Asset retirement obligations	'
	Note D. Asset retirement obligations
	The Company's asset retirement obligations primarily relate to the future plugging and abandonment of wells and facilities. The following table summarizes the Company's asset retirement obligation activity during the three months ended March 31, 2014 and 2013:
			Three Months Ended
			March 31,
	(in thousands)			2014		2013
	Asset retirement obligations, beginning of period		$	101,593	$	86,261
		Liabilities incurred from new wells		995		1,592
		Liabilities assumed in acquisitions		200		161
		Accretion expense		1,671		1,394
		Liabilities settled upon plugging and abandoning wells		-524		-1,157
		Revision of estimates		528		672
	Asset retirement obligations, end of period		$	104,463	$	88,923

Incentive_plans

Incentive plans	3 Months Ended														12 Months Ended
	Mar. 31, 2014														Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'														'
Incentive plans	'														'
	Note E. Incentive plans														The intrinsic value of options exercised during the three months ended March 31, 2014 and 2013 was approximately $6.1 million and $8.5 million, respectively, based on the difference between the market price at the exercise date and the option exercise price.
	Defined contribution plan. The Company sponsors a 401(k) defined contribution plan for the benefit of substantially all employees. Currently, the Company matches 100 percent of employee contributions, not to exceed 10 percent of the employee's annual salary. The Company's contributions to the plan for the three months ended March 31, 2014 and 2013, were approximately $1.9 million and $1.2 million, respectively, of which a portion was recoverable from other working interest owners.
	Stock incentive plan. The Company's 2006 Stock Incentive Plan, as amended and restated (the “Plan”), provides for granting stock options, restricted stock awards and performance awards to directors, officers and employees of the Company.
	Restricted stock awards. All restricted shares are legally issued and outstanding. If an employee terminates employment prior to the restriction lapse date, the awarded shares are forfeited and cancelled and are no longer considered issued and outstanding. A summary of the Company's restricted stock award activity for the three months ended March 31, 2014 is presented below:
								Weighted
								Average
					Number of			Grant Date
					Restricted			Fair Value
					Shares			Per Share
	Restricted stock:
		Outstanding at December 31, 2013			1,216,449
			Shares granted		134,989		$	108.42
			Shares cancelled / forfeited		-20,535
			Lapse of restrictions		-117,481
		Outstanding at March 31, 2014			1,213,422
	For restricted stock awards granted, stock-based compensation expense is being recognized in the Company's financial statements on an accelerated basis over the awards' vesting periods based on their fair values on the dates of grant. The restricted stock-based compensation awards generally vest over a period ranging from one to five years. The Company utilizes the average of the grant date's high and low stock prices for the fair value of restricted stock.
	The following table summarizes information about stock-based compensation for the Company's restricted stock awards activity under the Plan for the three months ended March 31, 2014 and 2013:
					Three Months Ended
					March 31,
	(in thousands)					2014			2013
	Grant date fair value for awards during the period (a)				$	14,636		$	11,979
	Stock-based compensation expense from restricted stock				$	8,839		$	5,760
	Income taxes and other information:
		Income tax benefit related to restricted stock			$	2,915		$	2,202
		Deductions in current taxable income related to restricted stock vestings			$	12,663		$	9,790
	(a)		The three months ended March 31, 2013 includes the effects of $1 million due to modifications of certain stock-based awards.
	Stock option awards.  A summary of the Company's stock option award activity under the Plan for the three months ended March 31, 2014 is presented below:
								Weighted
								Average
					Number of			Exercise
					Options			Price
	Stock options:
		Outstanding at December 31, 2013			255,537		$	21.5
			Options exercised		-60,676		$	20.67
		Outstanding at March 31, 2014			194,861		$	21.76
		Vested and exercisable at end of period			194,861		$	21.76
	The following table summarizes information about the Company's vested and exercisable stock options outstanding at March 31, 2014:
								Weighted
								Average			Weighted			Intrinsic
			Range of					Remaining			Average			Value
			Exercise			Number		Contractual			Exercise			of
			Prices			Vested		Life			Price			Options
														(in thousands)
		Vested and exercisable options:
			$12.00			8,536		1.74 years			$	12	$	943
			$12.50 - $15.50			15,000		3.38 years			$	12.85		1,645
			$20.00 - $23.00			140,770		4.41 years			$	21.23		14,256
			$28.00 - $37.27			30,555		4.14 years			$	31.33		2,786
						194,861		4.17 years			$	21.76	$	19,630
	The following table summarizes information about stock-based compensation for stock options for the three months ended March 31, 2014 and 2013:
				Three Months Ended
				March 31,
	(in thousands)					2014			2013
	Stock-based compensation expense from stock options				$	-		$	14
	Income taxes and other information:
		Income tax benefit related to stock options			$	-		$	5
		Deductions in current taxable income related to stock options exercised			$	6,138		$	8,501
	Performance unit awards. During the three months ended March 31, 2014 and 2013, the Company awarded performance units to its officers under the Plan. The number of shares of common stock that will ultimately be issued will be determined by a combination of (i) comparing the Company's total shareholder return relative to the total shareholder return of a predetermined group of peer companies at the end of the performance period and (ii) the Company's absolute total shareholder return at the end of the performance period. The performance period is 36 months. The grant date fair value was determined using the Monte Carlo simulation method and is being expensed ratably over the performance period. Expected volatilities utilized in the model were estimated using a historical period consistent with the remaining performance period of approximately three years. The risk-free interest rate was based on the United States Treasury rate for a term commensurate with the expected life of the grant.
	The Company used the following assumptions to estimate the fair value of performance unit awards granted during the three months ended March 31, 2014 and 2013:
					Three Months Ended
					March 31,
					2014			2013
	Risk-free interest rate				0.76%			0.37%
Range of volatilities				29.2% - 42.2%			31.5% - 45.1%
The following table summarizes the performance unit activity for the three months ended March 31, 2014:
					Number of			Grant Date
					Units (a)			Fair Value
Performance units:
	Outstanding at December 31, 2013				110,889
		Units granted			139,425		$	139.54
	Outstanding at March 31, 2014				250,314
(a)	Reflects the amount of performance units granted. The actual payout of shares will be between zero and 300 percent of the performance units granted depending on the Company's performance at the end of the performance period.
The following table summarizes information about stock-based compensation expense for performance units for the three months ended March 31, 2014:
				Three Months Ended
				March 31,
(in thousands)				2014				2013
Grant date fair value for awards during the period				$	19,455		$	12,353
Stock-based compensation expense from performance units				$	2,593		$	993
Income tax benefit related to performance units				$	975		$	380
Future stock-based compensation expense. The following table reflects the future stock-based compensation expense to be recorded for all the stock-based compensation awards that were outstanding at March 31, 2014:
				Restricted			Performance
(in thousands)				Stock			Units			Total
Remaining 2014			$	24,473		$	7,952		$	32,425
2015				18,531			10,639			29,170
2016				8,136			6,543			14,679
2017				1,670			-			1,670
2018				263			-			263
Thereafter				3			-			3
	Total		$	53,076		$	25,134		$	78,210

Disclosures_about_fair_value_o

Disclosures about fair value of financial instruments	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Disclosures about fair value of financial instruments	'
	Note F. Disclosures about fair value of financial instruments
	The Company uses a valuation framework based upon inputs that market participants use in pricing an asset or liability, which are classified into two categories: observable inputs and unobservable inputs. Observable inputs represent market data obtained from independent sources, whereas unobservable inputs reflect a company's own market assumptions, which are used if observable inputs are not reasonably available without undue cost and effort. These two types of inputs are further prioritized into the following fair value input hierarchy:
	Level 1:       Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. The Company considers active markets to be those in which transactions for the assets or liabilities occur in sufficient frequency and volume to provide pricing information on an ongoing basis.
	Level 2:       Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. This category includes those derivative instruments that the Company values using observable market data. Substantially all of these inputs are observable in the marketplace throughout the full term of the derivative instrument, can be derived from observable data, or supported by observable levels at which transactions are executed in the marketplace. Level 2 instruments primarily include non-exchange traded derivatives such as over-the-counter commodity price swaps, basis swaps, collars and floors, investments and interest rate swaps. The Company's valuation models are primarily industry-standard models that consider various inputs including: (i) quoted forward prices for commodities, (ii) time value and (iii) current market and contractual prices for the underlying instruments, as well as other relevant economic measures.
	Level 3:       Measured based on prices or valuation models that require inputs that are both significant to the fair value measurement and less observable from objective sources (i.e., supported by little or no market activity). The Company's valuation models are primarily industry-standard models that consider various inputs including: (i) quoted forward prices for commodities, (ii) time value, (iii) volatility factors and (iv) current market and contractual prices for the underlying instruments, as well as other relevant economic measures.
	Financial Assets and Liabilities Measured at Fair Value
	The following table presents the carrying amounts and fair values of the Company's financial instruments at March 31, 2014 and December 31, 2013
					31-Mar-14						31-Dec-13
					Carrying			Fair			Carrying			Fair
	(in thousands)				Value			Value			Value			Value
		Assets:
			Derivative instruments		$	1,627		$	1,627		$	1,556		$	1,556
		Liabilities:
			Derivative instruments		$	88,638		$	88,638		$	67,789		$	67,789
			Credit facility		$	294,650		$	298,722		$	250,000		$	250,770
			7.0% senior notes due 2021		$	600,000		$	661,500		$	600,000		$	660,000
			6.5% senior notes due 2022		$	600,000		$	654,000		$	600,000		$	649,500
			5.5% senior notes due 2022		$	600,000		$	625,500		$	600,000		$	619,500
			5.5% senior notes due 2023		$	1,579,784		$	1,642,975		$	1,580,421		$	1,627,834
	Cash and cash equivalents, accounts receivable, other current assets, accounts payable, interest payable and other current liabilities. The carrying amounts approximate fair value due to the short maturity of these instruments.
	Credit facility.  The fair value of the Company's credit facility is estimated by discounting the principal and interest payments at the Company's credit-adjusted discount rate at the reporting date, which utilizes inputs that are Level 2 measurements in the fair value hierarchy.
	Senior notes. The fair values of the Company's senior notes are based on quoted market prices. The debt securities are not actively traded and, therefore, are classified as Level 2 in the fair value hierarchy.
	Concentrations of credit risk. As of March 31, 2014, the Company's primary concentration of credit risks are the risk of collecting accounts receivable – trade and the risk of counterparties' failure to perform under derivative obligations.
	The Company has entered into International Swap Dealers Association Master Agreements (“ISDA Agreements”) with each of its derivative counterparties. The terms of the ISDA Agreements provide the Company and the counterparties with rights of set off upon the occurrence of defined acts of default by either the Company 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. See Note G for additional information regarding the Company's derivative activities.
	Derivative instruments. The fair value of the Company's derivative instruments is estimated by management considering various factors, including closing exchange and over-the-counter quotations and the time value of the underlying commitments. Financial assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurement. The Company's assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of the fair value of assets and liabilities and their placement within the fair value hierarchy levels. The following table summarizes (i) the valuation of each of the Company's financial instruments by required fair value hierarchy levels and (ii) the gross fair value by the appropriate balance sheet classification, even when the derivative instruments are subject to netting arrangements and qualify for net presentation in the Company's consolidated balance sheets at March 31, 2014 and December 31, 2013. The Company nets the fair value of derivative instruments by counterparty in the Company's consolidated balance sheets.
	31-Mar-14
						Fair Value Measurements Using															Net
						Quoted Prices													Gross		Fair Value
						in Active					Significant								Amounts		Presented
						Markets for					Other			Significant					Offset in the		in the
						Identical					Observable			Unobservable					Consolidated		Consolidated
						Assets					Inputs			Inputs			Total		Balance		Balance
	(in thousands)					(Level 1)					(Level 2)			(Level 3)			Fair Value		Sheet		Sheet
		Assets
			Current:
				Commodity derivatives			$	-		$	32,599		$	-		$	32,599	$	-31,241	$	1,358
			Noncurrent:
				Commodity derivatives				-			4,334			-			4,334		-4,065		269
		Liabilities
			Current:
				Commodity derivatives				-			-102,065			-			-102,065		31,241		-70,824
			Noncurrent:
				Commodity derivatives				-			-21,879			-			-21,879		4,065		-17,814
		Net derivative instruments					$	-		$	-87,011		$	-		$	-87,011	$	-	$	-87,011
	31-Dec-13
						Fair Value Measurements Using															Net
						Quoted Prices													Gross		Fair Value
						in Active					Significant								Amounts		Presented
						Markets for					Other			Significant					Offset in the		in the
						Identical					Observable			Unobservable					Consolidated		Consolidated
						Assets					Inputs			Inputs			Total		Balance		Balance
	(in thousands)					(Level 1)					(Level 2)			(Level 3)			Fair Value		Sheet		Sheet
		Assets
			Current:
				Commodity derivatives			$	-		$	12,819		$	-		$	12,819	$	-12,229	$	590
			Noncurrent:
				Commodity derivatives				-			5,300			-			5,300		-4,334		966
		Liabilities
			Current:
				Commodity derivatives				-			-65,930			-			-65,930		12,229		-53,701
			Noncurrent:
				Commodity derivatives				-			-18,422			-			-18,422		4,334		-14,088
		Net derivative instruments					$	-		$	-66,233		$	-		$	-66,233	$	-	$	-66,233
Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis
Certain assets and liabilities are reported at fair value on a nonrecurring basis in the Company's consolidated balance sheets.  The following methods and assumptions were used to estimate the fair values:
Impairments of long-lived assets – The Company reviews its long-lived assets to be held and used, including proved oil and natural gas properties, whenever events or circumstances indicate that the carrying value of those assets may not be recoverable, for instance when there are declines in commodity prices or well performance. An impairment loss is indicated if the sum of the expected undiscounted future net cash flows is less than the carrying amount of the assets. In this circumstance, the Company recognizes an impairment loss for the amount by which the carrying amount of the asset exceeds the estimated fair value of the asset. The Company reviews its oil and natural gas properties by depletion base or by individual well for those wells not constituting part of a depletion base. For each property determined to be impaired, an impairment loss equal to the difference between the carrying value of the properties and the estimated fair value of the properties would be recognized at that time.
The Company did not recognize any impairment charges for the three months ended March 31, 2014 or 2013.

Derivative_financial_instrumen

Derivative financial instruments	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative financial instruments	'
	Note G. Derivative financial instruments
	The Company uses derivative financial instruments to manage its exposure to commodity price fluctuations. Commodity derivative instruments are used to (i) reduce the effect of the volatility of price changes on the oil and natural gas the Company produces and sells, (ii) support the Company's capital budget and expenditure plans and (iii) support the economics associated with acquisitions. The Company does not enter into derivative financial instruments for speculative or trading purposes. The Company may also enter into physical delivery contracts to effectively provide commodity price hedges. Because these contracts are not expected to be net cash settled, they are considered to be normal sales contracts and not derivatives. Therefore, these contracts are not recorded in the Company's consolidated financial statements.
	The Company does not designate its derivative instruments to qualify for hedge accounting. Accordingly, the Company reflects changes in the fair value of its derivative instruments in its statements of operations as they occur.
	The following table summarizes the losses reported in earnings related to the commodity derivative instruments for the three months ended March 31, 2014 and 2013:
				Three Months Ended
				March 31,
	(in thousands)				2014			2013
	Loss on derivatives not designated as hedges:
		Oil derivatives		$	-24,220		$	-59,017
		Natural gas derivatives			-11,395			-
			Total loss on derivatives not designated as hedges	$	-35,615		$	-59,017
	The following table represents the Company's cash receipts from (payments on) derivatives reported in the Company's cash flows from investing for the three months ended March 31, 2014 and 2013:
				Three Months Ended
				March 31,
	(in thousands)				2014			2013
	Cash receipts from (payments on) derivatives not designated as hedges:
		Oil derivatives		$	-9,769		$	6,016
		Natural gas derivatives			-5,068			-
			Total cash receipts from (payments on) derivatives not designated as hedges	$	-14,837		$	6,016
	Commodity derivative contracts at March 31, 2014. The following table sets forth the Company's outstanding derivative contracts at March 31, 2014. When aggregating multiple contracts, the weighted average contract price is disclosed. All of the Company's derivative contracts at March 31, 2014 are expected to settle by June 30, 2017.
					First		Second		Third		Fourth
					Quarter		Quarter		Quarter		Quarter		Total
	Oil Swaps: (a)
		2014:00:00
			Volume (Bbl)				4,544,000		4,116,000		3,833,000		12,493,000
			Price per Bbl			$	92.69	$	91.23	$	91.09	$	91.72
		2015:00:00
			Volume (Bbl)		3,428,000		3,264,000		3,123,000		2,997,000		12,812,000
			Price per Bbl	$	87.33	$	86.54	$	86.8	$	86.75	$	86.86
		2016:00:00
			Volume (Bbl)		108,000		108,000		108,000		105,000		429,000
			Price per Bbl	$	88.32	$	88.32	$	88.32	$	88.28	$	88.31
		2017:00:00
			Volume (Bbl)		84,000		84,000		-		-		168,000
			Price per Bbl	$	87	$	87	$	-	$	-	$	87
	Oil Basis Swaps: (b)
		2014:00:00
			Volume (Bbl)				3,458,000		3,956,000		3,680,000		11,094,000
			Price per Bbl			$	-0.72	$	-0.99	$	-0.92	$	-0.88
	Natural Gas Swaps: (c)
		2014:00:00
			Volume (MMBtu)				3,335,000		2,576,000		2,053,000		7,964,000
			Price per MMBtu			$	4.22	$	4.23	$	4.24	$	4.23
		2015:00:00
			Volume (MMBtu)		5,850,000		5,915,000		5,980,000		5,980,000		23,725,000
			Price per MMBtu	$	4.16	$	4.16	$	4.16	$	4.16	$	4.16
	Natural Gas Collars: (d)
		2014:00:00
			Volume (MMBtu)				5,460,000		5,520,000		5,520,000		16,500,000
			Ceiling price per MMBtu			$	4.4	$	4.4	$	4.4	$	4.4
			Floor price per MMBtu			$	3.85	$	3.85	$	3.85	$	3.85
	(a) The index prices for the oil price swaps are based on the NYMEX – West Texas Intermediate ("WTI") monthly average futures price.
	(b) The basis differential price is between Midland – WTI and Cushing – WTI.
	(c) The index prices for the natural gas price swaps are based on the NYMEX – Henry Hub last trading day futures price.
	(d) The index prices for the natural gas collars are based on the El Paso Permian delivery point.
	Derivative counterparties.  The Company uses credit and other financial criteria to evaluate the credit standing of, and to select, counterparties to its derivative instruments. Although the Company does not obtain collateral or otherwise secure the fair value of its derivative instruments, associated credit risk is mitigated by the Company's credit risk policies and procedures.
				Three Months Ended
				March 31,
	(in thousands)				2014			2013
	Loss on derivatives not designated as hedges:
		Oil derivatives		$	-24,220		$	-59,017
		Natural gas derivatives			-11,395			-
			Total loss on derivatives not designated as hedges	$	-35,615		$	-59,017
The following table represents the Company's cash receipts from (payments on) derivatives reported in the Company's cash flows from investing for the three months ended March 31, 2014 and 2013:
			Three Months Ended
			March 31,
(in thousands)				2014			2013
Cash receipts from (payments on) derivatives not designated as hedges:
	Oil derivatives		$	-9,769		$	6,016
	Natural gas derivatives			-5,068			-
		Total cash receipts from (payments on) derivatives not designated as hedges	$	-14,837		$	6,016

Debt

Debt	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Debt	'
	Note H. Debt
	The Company's debt consisted of the following at March 31, 2014 and December 31, 2013:
						March 31,			December 31,
	(in thousands)					2014			2013
	Credit facility				$	294,650		$	250,000
	7.0% unsecured senior notes due 2021					600,000			600,000
	6.5% unsecured senior notes due 2022					600,000			600,000
	5.5% unsecured senior notes due 2022					600,000			600,000
	5.5% unsecured senior notes due 2023					1,550,000			1,550,000
	Unamortized original issue premium, net					29,784			30,421
		Less: current portion				-			-
			Total long-term debt		$	3,674,434		$	3,630,421
	Credit facility. The Company's credit facility, as of March 31, 2014, has a maturity date of April 25, 2016. As of March 31, 2014, the Company's borrowing base is $3.0 billion and commitments from the Company's bank group total $2.5 billion. See Note P for a subsequent event regarding the Company's amended and restated credit facility that was executed on May 9, 2014.
	Senior notes. Interest on the Company's senior notes is paid in arrears semi-annually. The senior notes are fully and unconditionally guaranteed on a senior unsecured basis by all subsidiaries of the Company, subject to customary release provisions as described in Note O.
	At March 31, 2014, the Company was in compliance with the covenants under all of its debt instruments.
	Future benefit to interest expense from original issue premium at March 31, 2014 was as follows:
	(in thousands)
	Remaining 2014			$		1,964
	2015					2,747
	2016					2,900
	2017					3,062
	2018					3,233
	2019					3,413
	Thereafter					12,465
		Total		$		29,784
	Principal maturities of long-term debt. Principal maturities of long-term debt outstanding at March 31, 2014 were as follows:
	(in thousands)
	Remaining 2014			$		-
	2015					-
	2016					294,650
	2017					-
	2018					-
	2019					-
	Thereafter					3,350,000
		Total		$		3,644,650
	Interest expense. The following amounts have been incurred and charged to interest expense for the three months ended March 31, 2014 and 2013:
							Three Months Ended
							March 31,
	(in thousands)							2014			2013
	Cash payments for interest						$	44,320		$	43,988
	Amortization of original issue discount (premium)							-637			123
	Amortization of deferred loan origination costs							3,347			3,254
	Net changes in accruals							9,105			4,741
		Total interest expense					$	56,135		$	52,106

Commitments_and_contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and contingencies	'
	Note I. Commitments and contingencies
	Severance agreements. The Company has entered into severance and change in control agreements with all of its officers. The current annual salaries for the Company's officers covered under such agreements total approximately $7.0 million.
	Indemnifications. The Company has agreed to indemnify its directors and officers with respect to claims and damages arising from certain acts or omissions taken in such capacity.
	Legal actions. The Company is a party to proceedings and claims incidental to its business. While many of these matters involve inherent uncertainty, the Company believes that the amount of the liability, if any, ultimately incurred with respect to any such proceedings or claims will not have a material adverse effect on the Company's consolidated financial position as a whole or on its liquidity, capital resources or future results of operations. The Company will continue to evaluate proceedings and claims involving the Company on a regular basis and will establish and adjust any reserves as appropriate to reflect its assessment of the then current status of the matters.
	Severance tax, royalty and joint interest audits.  The Company is subject to routine severance, royalty and joint interest audits from regulatory bodies and non-operators and makes accruals as necessary for estimated exposure when deemed probable and estimable. Additionally, the Company is subject to various possible contingencies that arise primarily from interpretations affecting the oil and natural gas industry.  Such contingencies include differing interpretations as to the prices at which oil and natural gas sales may be made, the prices at which royalty owners may be paid for production from their leases, allowable costs under joint interest arrangements and other matters. At March 31, 2014 and December 31, 2013, the Company had $12.7 million and $12.2 million accrued for estimated exposure, respectively. Although we believe that we have estimated our exposure with respect to the various laws and regulations, administrative rulings and interpretations thereof, adjustments could be required as new interpretations and regulations are issued.
	Contractual drilling commitments.  The Company periodically enters into contractual arrangements under which the Company is committed to expend funds to drill wells in the future, including agreements to secure drilling rig services, which require the Company to make future minimum payments to the rig operators. The Company records drilling commitments in the periods in which well capital is incurred or rig services are provided. The following table summarizes the Company's future drilling commitments at March 31, 2014:
			Payments Due By Period
							Less than		3-Jan		5-Mar		More than
	(in thousands)			Total			1 year		years		years		5 years
	Contractual drilling commitments		$	11,288		$	11,288	$	-	$	-	$	-
	Operating leases. The Company leases vehicles, equipment and office facilities under non-cancellable operating leases. Lease payments associated with these operating leases for the three months ended March 31, 2014 and 2013 were approximately $1.7 million and $1.2 million, respectively.
	Future minimum lease commitments under non-cancellable operating leases at March 31, 2014 were as follows:
	(in thousands)
	Remaining 2014			$	4,966
	2015				5,546
	2016				4,202
	2017				4,411
	2018				3,928
	2019				3,980
	Thereafter				8,659
		Total		$	35,692

Income_taxes

Income taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income taxes	'
	Note J. Income taxes
	The effective income tax rates for the three months ended March 31, 2014 and 2013 were 37.7 percent and 38.5 percent, respectively. During the fourth quarter of 2013, the Company revised its estimated blended effective state rate to consider (a) New Mexico legislation passed that phases in a tax rate reduction from 7.6 percent to 5.9 percent in 2018 and (b) the apportionment factor for states in which the Company operates. Total income tax expense for the three months ended March 31, 2014 and 2013 differed from amounts computed by applying the U.S. federal statutory tax rates to pre-tax income due primarily to state taxes and the impact of permanent differences between book and taxable income.

Related_party_transactions

Related party transactions	3 Months Ended
	Mar. 31, 2014
Related Party Transactions [Abstract]	'
Related party transactions	'
	Note K. Related party transactions
	The following table summarizes charges incurred with and payments made to related parties and reported in the Company's consolidated statements of operations for the periods presented:
		Three Months Ended
		March 31,
	(in thousands)		2014		2013
	Royalties paid to a partnership in which a director has an ownership interest (a)	$	2,802	$	1,340
	Royalties paid to a director and certain officers of the Company (b)	$	97	$	10
	Amounts paid under consulting agreement with Steven L. Beal (c)	$	-	$	60
	Royalties paid on certain properties to a partnership of which a director of the Company is the general partner and owns a 3.5 percent partnership interest.
	Payments made to a director and certain officers who directly own overriding royalty interests in properties owned by the Company.
	On June 30, 2009, Steven L. Beal, the Company's then-president and chief operating officer, retired from such positions. On June 9, 2009, the Company entered into a consulting agreement (the “Consulting Agreement”) with Mr. Beal, under which Mr. Beal began serving as a consultant to the Company on July 1, 2009. During the term of the consulting relationship, Mr. Beal received a consulting fee of $20,000 per month and a monthly reimbursement for his medical and dental coverage costs. In August 2013, the Company and Mr. Beal mutually terminated the Consulting Agreement in exchange for the payment to Mr. Beal of $720,000, which termination and payment were approved by the disinterested members of the Company's Board of Directors.

Discontinued_operations

Discontinued operations	3 Months Ended
	Mar. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]	'
Discontinued operations	'
	Note L. Discontinued operations
	In December 2012, the Company closed the sale of certain of its non-core assets for cash consideration of approximately $503.1 million. As a result of post-closing adjustments during the three months ended March 31, 2013, the Company made a positive adjustment to gain (loss) on disposition of assets of approximately $20.4 million, before income tax expense of approximately $7.9 million. The Company reflected the net post-closing adjustment of approximately $12.5 million as discontinued operations

Net_income_per_share

Net income per share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]	'
Net income per share	'
	Note M. Net income per share
	The Company uses the two-class method of calculating net income per share because certain of the Company's unvested share-based awards qualify as participating securities. Participating securities participate in income proportionate to the weighted average number of outstanding common shares (although all restricted stock is issued and outstanding upon grant), but are not assumed to participate in the Company's net losses because they are not contractually obligated to do so. Accordingly, allocations of earnings to participating securities are included in the Company's calculations of basic and diluted earnings per share from continuing operations, discontinued operations and net income attributable to common stockholders.
	The following tables reconcile the Company's income from continuing operations, income from discontinued operations and net income attributable to common stockholders to the basic and diluted earnings used to determine the Company's income per share amounts for the three months ended March 31, 2014 and 2013, respectively, under the two-class method:
						Three Months Ended
						31-Mar-14
					Continuing			Discontinued
	(in thousands, except per share amounts)				Operations			Operations		Total
	Income as reported				$	91,307		$	-	$	91,307
	Participating basic earnings					-1,068			-		-1,068
		Basic income attributable to common stockholders				90,239			-		90,239
	Reallocation of participating earnings					4			-		4
		Diluted income attributable to common stockholders			$	90,243		$	-	$	90,243
	Income per common share:
		Basic			$	0.87		$	-	$	0.87
		Diluted			$	0.87		$	-	$	0.87
						Three Months Ended
						31-Mar-13
					Continuing			Discontinued
	(in thousands, except per share amounts)				Operations			Operations		Total
	Income as reported				$	17,559		$	12,534	$	30,093
	Participating basic earnings					-			-		-
		Basic income attributable to common stockholders				17,559			12,534		30,093
	Reallocation of participating earnings					-			-		-
		Diluted income attributable to common stockholders			$	17,559		$	12,534	$	30,093
	Income per common share:
		Basic			$	0.17		$	0.12	$	0.29
		Diluted			$	0.17		$	0.12	$	0.29
	The following table is a reconciliation of the basic weighted average common shares outstanding to diluted weighted average common shares outstanding for the three months ended March 31, 2014 and 2013:
					Three Months Ended
					March 31,
	(in thousands)				2014		2013
	Weighted average common shares outstanding:
		Basic			103,949		103,631
			Dilutive common stock options		123		204
			Dilutive restricted stock		-		510
			Dilutive performance units		234		-
		Diluted			104,306		104,345
	The following table is a summary of the common stock options, restricted stock and performance units, which were not included in the computation of diluted net income per share, as inclusion of these items would be antidilutive:
				Three Months Ended
				March 31,
	(in thousands)			2014		2013
	Number of antidilutive common shares:
		Antidilutive restricted stock		46		13
		Antidilutive performance units		-		111

Other_current_liabilities

Other current liabilities	3 Months Ended
	Mar. 31, 2014
Other Liabilities Disclosure [Abstract]	'
Other current liabilities	'
	Note N. Other current liabilities
	The following table provides the components of the Company's other current liabilities at March 31, 2014 and December 31, 2013:
					March 31,		December 31,
	(in thousands)				2014		2013
	Other current liabilities:
		Accrued production costs		$	46,553	$	48,196
		Payroll related matters			30,863		28,498
		Accrued interest			79,105		70,000
		Settlements due on derivatives			2,993		1,175
		Asset retirement obligations			4,982		4,481
		Other			6,740		4,250
			Other current liabilities	$	171,236	$	156,600

Subsidiary_guarantors

Subsidiary guarantors	3 Months Ended
	Mar. 31, 2014
Guarantees [Abstract]	'
Subsidiary guarantors	'
	Note O. Subsidiary guarantors
	Certain of the Company's wholly-owned subsidiaries have fully and unconditionally guaranteed the Company's senior notes. The indentures governing the Company's senior notes provide that the guarantees of its subsidiary guarantors will be released in certain customary circumstances, including (i) in connection with any sale, exchange or other disposition, whether by merger, consolidation or otherwise, of the capital stock of that guarantor to a person that is not the Company or a restricted subsidiary of the Company, such that, after giving effect to such transaction, such guarantor would no longer constitute a subsidiary of the Company, (ii) in connection with any sale, exchange or other disposition (other than a lease) of all or substantially all of the assets of that guarantor to a person that is not the Company or a restricted subsidiary of the Company, (iii) upon the merger of a guarantor into the Company or any other guarantor or the liquidation or dissolution of a guarantor, (iv) if the Company designates any restricted subsidiary that is a guarantor to be an unrestricted subsidiary in accordance with the indenture, (v) upon legal defeasance or satisfaction and discharge of the indenture and (vi) upon written notice of such release or discharge by the Company to the trustee following the release or discharge of all guarantees by such guarantor of any indebtedness that resulted in the creation of such guarantee, except a discharge or release by or as a result of payment under such guarantee.
	See Note H for a summary of the Company's senior notes. In accordance with practices accepted by the United States Securities and Exchange Commission, the Company has prepared condensed consolidating financial statements in order to quantify the assets, results of operations and cash flows of such subsidiaries as subsidiary guarantors.
	The following condensed consolidating balance sheets at March 31, 2014 and December 31, 2013, condensed consolidating statements of operations and condensed consolidating statements of cash flows for the three months ended March 31, 2014 and 2013 present financial information for Concho Resources Inc. as the Parent on a stand-alone basis (carrying any investments in subsidiaries under the equity method), financial information for the subsidiary guarantors on a stand-alone basis and the consolidation and elimination entries necessary to arrive at the information for the Company on a consolidated basis. All current and deferred income taxes are recorded on Concho Resources Inc., as the subsidiaries are flow-through entities for income tax purposes. The subsidiary guarantors are not restricted from making distributions to the Company.
	Condensed Consolidating Balance Sheet
	31-Mar-14
				Parent			Subsidiary			Consolidating
	(in thousands)			Issuer			Guarantors			Entries			Total
	ASSETS
	Accounts receivable - related parties		$	6,092,946		$	1,244,197		$	-7,337,143		$	-
	Other current assets			40,628			534,803			-			575,431
	Oil and natural gas properties, net			-			9,167,502			-			9,167,502
	Property and equipment, net			-			116,159			-			116,159
	Investment in subsidiaries			4,135,667			-			-4,135,667			-
	Other long-term assets			69,970			49,106			-			119,076
		Total assets	$	10,339,211		$	11,111,767		$	-11,472,810		$	9,978,168
	LIABILITIES AND EQUITY
	Accounts payable - related parties		$	1,244,197		$	6,092,946		$	-7,337,143		$	-
	Other current liabilities			155,002			783,602			-			938,604
	Other long-term liabilities			1,404,391			99,552			-			1,503,943
	Long-term debt			3,674,434			-			-			3,674,434
	Equity			3,861,187			4,135,667			-4,135,667			3,861,187
		Total liabilities and equity	$	10,339,211		$	11,111,767		$	-11,472,810		$	9,978,168
	Condensed Consolidating Balance Sheet
	31-Dec-13
				Parent			Subsidiary			Consolidating
	(in thousands)			Issuer			Guarantors			Entries			Total
	ASSETS
	Accounts receivable - related parties		$	6,115,554		$	1,261,844		$	-7,377,398		$	-
	Other current assets			39,108			481,767			-			520,875
	Oil and natural gas properties, net			-			8,831,265			-			8,831,265
	Property and equipment, net			-			114,783			-			114,783
	Investment in subsidiaries			3,896,741			-			-3,896,741			-
	Other long-term assets			74,013			50,228			-			124,241
		Total assets	$	10,125,416		$	10,739,887		$	-11,274,139		$	9,591,164
	LIABILITIES AND EQUITY
	Accounts payable - related parties		$	1,261,844		$	6,115,554		$	-7,377,398		$	-
	Other current liabilities			126,461			630,407			-			756,868
	Other long-term liabilities			1,348,741			97,185			-			1,445,926
	Long-term debt			3,630,421			-			-			3,630,421
	Equity			3,757,949			3,896,741			-3,896,741			3,757,949
		Total liabilities and equity	$	10,125,416		$	10,739,887		$	-11,274,139		$	9,591,164
	Condensed Consolidating Statement of Operations
	Three Months Ended March 31, 2014
				Parent			Subsidiary			Consolidating
	(in thousands)			Issuer			Guarantors			Entries			Total
	Total operating revenues		$	-		$	660,959		$	-		$	660,959
	Total operating costs and expenses			-36,153			-422,574			-			-458,727
		Income (loss) from operations		-36,153			238,385			-			202,232
	Interest expense			-56,135			-			-			-56,135
	Other, net			238,926			541			-238,926			541
		Income before income taxes		146,638			238,926			-238,926			146,638
	Income tax expense			-55,331			-			-			-55,331
		Net income	$	91,307		$	238,926		$	-238,926		$	91,307
	Condensed Consolidating Statement of Operations
	Three Months Ended March 31, 2013
				Parent			Subsidiary			Consolidating
	(in thousands)			Issuer			Guarantors			Entries			Total
	Total operating revenues		$	-		$	472,127		$	-		$	472,127
	Total operating costs and expenses			-59,196			-332,180			-			-391,376
		Income (loss) from continuing operations		-59,196			139,947			-			80,751
	Interest expense			-52,106			-			-			-52,106
	Other, net			160,201			-109			-160,201			-109
	Income from continuing operations before income taxes		48,899			139,838			-160,201			28,536
Income tax expense			-10,977			-			-			-10,977
	Income from continuing operations		37,922			139,838			-160,201			17,559
Income (loss) from discontinued operations, net of tax			-7,829			20,363			-			12,534
	Net income	$	30,093		$	160,201		$	-160,201		$	30,093
Condensed Consolidating Statement of Cash Flows
Three Months Ended March 31, 2014
				Parent			Subsidiary			Consolidating
(in thousands)				Issuer			Guarantors			Entries			Total
Net cash flows provided by (used in) operating activities			$	-30,312		$	506,292		$	-		$	475,980
Net cash flows used in investing activities				-14,837			-559,859			-			-574,696
Net cash flows provided by financing activities				45,149			53,567			-			98,716
	Net decrease in cash and cash equivalents			-			-			-			-
	Cash and cash equivalents at beginning of period			-			21			-			21
	Cash and cash equivalents at end of period		$	-		$	21		$	-		$	21
Condensed Consolidating Statement of Cash Flows
Three Months Ended March 31, 2013
				Parent			Subsidiary			Consolidating
(in thousands)				Issuer			Guarantors			Entries			Total
Net cash flows provided by (used in) operating activities			$	-171,843		$	391,514		$	-		$	219,671
Net cash flows provided by (used in) investing activities				6,016			-408,145			-			-402,129
Net cash flows provided by financing activities				165,827			14,725			-			180,552
	Net decrease in cash and cash equivalents			-			-1,906			-			-1,906
	Cash and cash equivalents at beginning of period			-			2,880			-			2,880
	Cash and cash equivalents at end of period		$	-		$	974		$	-		$	974

Subsequent_events

Subsequent events	3 Months Ended
	Mar. 31, 2014
Subsequent Events [Abstract]	'
Subsequent events	'
	Note P. Subsequent events
	New commodity derivative contracts. After March 31, 2014, the Company entered into the following oil price swaps, oil basis swaps and natural gas basis swaps to hedge additional amounts of the Company's estimated future production:
					First		Second		Third		Fourth
					Quarter		Quarter		Quarter		Quarter		Total
	Oil Swaps: (a)
		2014:00:00
			Volume (Bbl)				440,000		455,000		340,000		1,235,000
			Price per Bbl			$	99.9	$	99.53	$	99.12	$	99.55
		2015:00:00
			Volume (Bbl)		360,000		360,000		210,000		210,000		1,140,000
			Price per Bbl	$	91.5	$	91.5	$	90.76	$	90.76	$	91.23
	Oil Basis Swaps: (b)
		2014:00:00
			Volume (Bbl)				-		-		276,000		276,000
			Price per Bbl			$	-	$	-	$	-3	$	-3
		2015:00:00
			Volume (Bbl)		270,000		273,000		-		-		543,000
			Price per Bbl	$	-3	$	-3	$	-	$	-	$	-3
	Natural Gas Basis Swaps: (c)
		2014:00:00
			Volume (MMBtu)				1,220,000		1,840,000		1,840,000		4,900,000
			Price per MMBtu			$	-0.11	$	-0.11	$	-0.11	$	-0.11
	(a)	The index prices for the oil price swaps are based on the NYMEX – WTI monthly average futures price.
	(b)	The basis differential price is between Midland – WTI and Cushing – WTI.
	(c)	The basis differential price is between the El Paso Permian delivery point and NYMEX – Henry Hub delivery point.
	Delaware Basin midstream agreements. On May 9, 2014, the Company signed an agreement, with an unrelated third party, to own 50 percent of a new midstream joint venture. The joint venture was formed to build a crude oil pipeline to transport production in the northern Delaware Basin. The Company's 50 percent share of the joint venture's capital expenditures is estimated to be approximately $95.0 million. The Company expects the system to be operational in the second half of 2015.
	Additionally, on May 9, 2014, the Company entered into a ten year crude petroleum dedication and transportation agreement with the joint venture. Under the terms of the agreement and subject to certain regulatory approvals, the Company is obligated to deliver oil production to the joint venture from a substantial portion of the properties that the Company currently operates in the northern Delaware Basin area, as well as future oil production from future development of certain of the Company's northern Delaware Basin acreage.
	Amended and restated credit facility. On May 9, 2014, the Company amended and restated its credit facility. The Company increased its borrowing base from $3.0 billion to $3.25 billion while maintaining the aggregate lender commitments at $2.5 billion. The maturity date of the amended and restated credit facility is May 9, 2019. The collateral securing the facility may be released at the Company's election. Additionally, the new facility provides for a 25 basis point reduction in the drawn spread and further interest rate reductions on the undrawn spread. The Company expects to write-off approximately $4.3 million in capitalized deferred loan costs incurred with the previous credit facility.
					First		Second		Third		Fourth
					Quarter		Quarter		Quarter		Quarter		Total
	Oil Swaps: (a)
		2014:00:00
			Volume (Bbl)				440,000		455,000		340,000		1,235,000
			Price per Bbl			$	99.9	$	99.53	$	99.12	$	99.55
		2015:00:00
			Volume (Bbl)		360,000		360,000		210,000		210,000		1,140,000
			Price per Bbl	$	91.5	$	91.5	$	90.76	$	90.76	$	91.23
	Oil Basis Swaps: (b)
		2014:00:00
			Volume (Bbl)				-		-		276,000		276,000
			Price per Bbl			$	-	$	-	$	-3	$	-3
		2015:00:00
			Volume (Bbl)		270,000		273,000		-		-		543,000
			Price per Bbl	$	-3	$	-3	$	-	$	-	$	-3
	Natural Gas Basis Swaps: (c)
		2014:00:00
			Volume (MMBtu)				1,220,000		1,840,000		1,840,000		4,900,000
			Price per MMBtu			$	-0.11	$	-0.11	$	-0.11	$	-0.11
	(a)	The index prices for the oil price swaps are based on the NYMEX – WTI monthly average futures price.
	(b)	The basis differential price is between Midland – WTI and Cushing – WTI.
	(c)	The basis differential price is between the El Paso Permian delivery point and NYMEX – Henry Hub delivery point.

Supplementary_information

Supplementary information	3 Months Ended
	Mar. 31, 2014
Oil and Gas Exploration and Production Industries Disclosures [Abstract]	'
Supplementary information	'
	Note Q. Supplementary information
	Capitalized costs
				March 31,		December 31,
	(in thousands)			2014		2013
	Oil and natural gas properties:
		Proved		$	10,708,779	$	10,182,953
		Unproved			1,059,636		1,032,420
		Less: accumulated depletion			-2,600,913		-2,384,108
			Net capitalized costs for oil and natural gas properties	$	9,167,502	$	8,831,265
	Costs incurred for oil and natural gas producing activities (a)
				Three Months Ended
				March 31,
	(in thousands)			2014		2013
	Property acquisition costs:
		Proved		$	20,490	$	1,885
		Unproved			24,688		27,896
	Exploration				324,497		266,690
	Development				211,679		174,722
		Total costs incurred for oil and natural gas properties		$	581,354	$	471,193
	(a)	The costs incurred for oil and natural gas producing activities includes the following amounts of asset retirement obligations:
				Three Months Ended
				March 31,
		(in thousands)		2014		2013
		Exploration costs		$	558	$	734
		Development costs			965		1,530
			Total asset retirement obligations	$	1,523	$	2,264
				Three Months Ended
				March 31,
	(in thousands)			2014		2013
	Property acquisition costs:
		Proved		$	20,490	$	1,885
		Unproved			24,688		27,896
	Exploration				324,497		266,690
	Development				211,679		174,722
		Total costs incurred for oil and natural gas properties		$	581,354	$	471,193
	(a)	The costs incurred for oil and natural gas producing activities includes the following amounts of asset retirement obligations:
				Three Months Ended
				March 31,
		(in thousands)		2014		2013
		Exploration costs		$	558	$	734
		Development costs			965		1,530
			Total asset retirement obligations	$	1,523	$	2,264

Summary_of_significant_account1

Summary of significant accounting policies (Policies)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Principles of consolidation	'
	Principles of consolidation. The consolidated financial statements of the Company include the accounts of the Company and its wholly-owned subsidiaries. The Company consolidates the financial statements of these entities. All material intercompany balances and transactions have been eliminated.
Use of estimates in the preparation of financial statements	'
	Use of estimates in the preparation of financial statements.  Preparation of financial statements in conformity with generally accepted accounting principles in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from these estimates. Depletion of oil and natural gas properties is determined using estimates of proved oil and natural gas reserves. There are numerous uncertainties inherent in the estimation of quantities of proved reserves and in the projection of future rates of production and the timing of development expenditures. Similarly, evaluations for impairment of proved and unproved oil and natural gas properties are subject to numerous uncertainties including, among others, estimates of future recoverable reserves and commodity price outlooks. Other significant estimates include, but are not limited to, the asset retirement obligations, fair value of derivative financial instruments, the fair value of business combinations, fair value of stock-based compensation and income taxes.
Interim Financial Statements [Policy Text Block]	'
	Interim financial statements. The accompanying consolidated financial statements of the Company have not been audited by the Company's independent registered public accounting firm, except that the consolidated balance sheet at December 31, 2013 is derived from audited consolidated financial statements. In the opinion of management, the accompanying consolidated financial statements reflect all adjustments necessary to present fairly the Company's consolidated financial statements. All such adjustments are of a normal, recurring nature. In preparing the accompanying consolidated financial statements, management has made certain estimates and assumptions that affect reported amounts in the consolidated financial statements and disclosures of contingencies. Actual results may differ from those estimates. The results for interim periods are not necessarily indicative of annual results.
	Certain disclosures have been condensed in or omitted from these consolidated financial statements. Accordingly, these condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2013.
Deferred loan costs.	'
	Deferred loan costs. Deferred loan costs are stated at cost, net of amortization, which is computed using the effective interest and straight-line methods. The Company had deferred loan costs of $69.7 million and $73.0 million, net of accumulated amortization of $52.1 million and $48.7 million, at March 31, 2014 and December 31, 2013, respectively.
	The following table reflects the future amortization expense of deferred loan costs at March 31, 2014:
	(in thousands)
	Remaining 2014		$	10,156
	2015			13,820
	2016			8,476
	2017			5,994
	2018			6,376
	2019			6,784
	Thereafter			18,095
		Total	$	69,701
Intangible assets.	'
	Intangible assets. The Company has capitalized certain operating rights acquired in an acquisition. The gross operating rights, which have no residual value, are amortized over the estimated economic life of 25 years. Impairment will be assessed if indicators of potential impairment exist or when there is a material change in the remaining useful economic life. The following table reflects the gross and net intangible assets at March 31, 2014 and December 31, 2013:
				March 31,		December 31,
	(in thousands)			2014		2013
	Gross intangible - operating rights		$	36,557	$	36,557
	Accumulated amortization			-8,307		-7,942
		Net intangible - operating rights	$	28,250	$	28,615
	The following table reflects amortization expense for the three months ended March 31, 2014 and 2013:
			Three Months Ended
			March 31,
	(in thousands)		2014		2013
	Amortization expense		$	365	$	365
	The following table reflects the estimated aggregate amortization expense for each of the periods presented below at March 31, 2014:
	(in thousands)
	Remaining 2014		$	1,096
	2015			1,461
	2016			1,461
	2017			1,461
	2018			1,461
	2019			1,461
	Thereafter			19,849
		Total	$	28,250
Revenue recognition	'
	Revenue recognition. Oil and natural gas revenues are recorded at the time of physical transfer of such products to the purchaser, which for the Company is primarily at the wellhead. The Company follows the sales method of accounting for oil and natural gas sales, recognizing revenues based on the Company's share of actual proceeds from the oil and natural gas sold to purchasers.
General and administrative expense.	'
	General and administrative expense. The Company receives fees for the operation of jointly-owned oil and natural gas properties and records such reimbursements as reductions of general and administrative expense. Such fees totaled approximately $5.1 million and $4.2 million for the three months ended March 31, 2014 and 2013, respectively.
Recent accounting pronouncements	'
	Recent accounting pronouncements. In April 2014, the Financial Accounting Standards Board issued guidance that raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. Under the revised standard, a discontinued operation is (i) a component of an entity or group of components that has been disposed of by sale, disposed of other than by sale or is classified as held for sale that represents a strategic shift that has or will have a major effect on an entity's operations and financial results or (ii) an acquired business or nonprofit activity that is classified as held for sale on the date of the acquisition. This update is aimed at reducing the frequency of disposals reported as discontinued operations by focusing on strategic shifts that have or will have a major effect on an entity's operations and financial results.
	An entity is required to apply this guidance for annual reporting periods beginning on or after December 15, 2014, and interim periods within those annual periods, though earlier adoption is permitted. An entity should provide the disclosures required by this amendment prospectively. The Company is evaluating the impact of this new guidance and does not expect it to have a significant impact on the consolidated financial statements.

Summary_of_significant_account2

Summary of significant accounting policies (Tables)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Schedule Of Expected Amortization Expense Table [Text Block]	'
	(in thousands)
	Remaining 2014		$	10,156
	2015			13,820
	2016			8,476
	2017			5,994
	2018			6,376
	2019			6,784
	Thereafter			18,095
		Total	$	69,701
	(in thousands)
	Remaining 2014		$	1,096
	2015			1,461
	2016			1,461
	2017			1,461
	2018			1,461
	2019			1,461
	Thereafter			19,849
		Total	$	28,250
Schedule Of Amortization Expense [Table Text Block]	'
				March 31,		December 31,
	(in thousands)			2014		2013
	Gross intangible - operating rights		$	36,557	$	36,557
	Accumulated amortization			-8,307		-7,942
		Net intangible - operating rights	$	28,250	$	28,615
			Three Months Ended
			March 31,
	(in thousands)		2014		2013
	Amortization expense		$	365	$	365

Exploratory_well_costs_Tables

Exploratory well costs (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure Exploratory Well Costs Capitalized Exploratory Well Activity [Abstract]	'
Company's capitalized exploratory well activity	'
			Three Months Ended
	(in thousands)		31-Mar-14
	Beginning capitalized exploratory well costs			$	144,504
		Additions to exploratory well costs pending the determination of proved reserves			134,660
		Reclassifications due to determination of proved reserves			-86,904
		Exploratory well costs charged to expense			-19,286
	Ending capitalized exploratory well costs			$	172,974
Aging of capitalized exploratory well costs based on the date drilling was completed	'
					March 31,		December 31,
	(dollars in thousands)				2014		2013
	Capitalized exploratory well costs that have been capitalized for a period of one year or less			$	152,891	$	122,753
	Capitalized exploratory well costs that have been capitalized for a period greater than one year				20,083		21,751
		Total capitalized exploratory well costs		$	172,974	$	144,504
	Number of projects with exploratory well costs that have been capitalized for a period greater
		than one year			12		10

Asset_retirement_obligations_T

Asset retirement obligations (Tables)	3 Months Ended
	Mar. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]	'
Asset retirement obligations	'
	The Company's asset retirement obligations primarily relate to the future plugging and abandonment of wells and facilities. The following table summarizes the Company's asset retirement obligation activity during the three months ended March 31, 2014 and 2013:
			Three Months Ended
			March 31,
	(in thousands)			2014		2013
	Asset retirement obligations, beginning of period		$	101,593	$	86,261
		Liabilities incurred from new wells		995		1,592
		Liabilities assumed in acquisitions		200		161
		Accretion expense		1,671		1,394
		Liabilities settled upon plugging and abandoning wells		-524		-1,157
		Revision of estimates		528		672
	Asset retirement obligations, end of period		$	104,463	$	88,923

Incentive_plans_Tables

Incentive plans (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Summary of the Company's restricted stock awards activity	'
	A summary of the Company's restricted stock award activity for the three months ended March 31, 2014 is presented below:
								Weighted
								Average
					Number of			Grant Date
					Restricted			Fair Value
					Shares			Per Share
	Restricted stock:
		Outstanding at December 31, 2013			1,216,449
			Shares granted		134,989		$	108.42
			Shares cancelled / forfeited		-20,535
			Lapse of restrictions		-117,481
		Outstanding at March 31, 2014			1,213,422
Summarizes information about stock-based compensation for the Company's restricted stock awards activity under the Plan	'
	For restricted stock awards granted, stock-based compensation expense is being recognized in the Company's financial statements on an accelerated basis over the awards' vesting periods based on their fair values on the dates of grant. The restricted stock-based compensation awards generally vest over a period ranging from one to five years. The Company utilizes the average of the grant date's high and low stock prices for the fair value of restricted stock.
	The following table summarizes information about stock-based compensation for the Company's restricted stock awards activity under the Plan for the three months ended March 31, 2014 and 2013:
					Three Months Ended
					March 31,
	(in thousands)					2014			2013
	Grant date fair value for awards during the period (a)				$	14,636		$	11,979
	Stock-based compensation expense from restricted stock				$	8,839		$	5,760
	Income taxes and other information:
		Income tax benefit related to restricted stock			$	2,915		$	2,202
		Deductions in current taxable income related to restricted stock vestings			$	12,663		$	9,790
	(a)		The three months ended March 31, 2013 includes the effects of $1 million due to modifications of certain stock-based awards.
Summary of the Company's stock option awards activity under the Plan	'
	Stock option awards.  A summary of the Company's stock option award activity under the Plan for the three months ended March 31, 2014 is presented below:
								Weighted
								Average
					Number of			Exercise
					Options			Price
	Stock options:
		Outstanding at December 31, 2013			255,537		$	21.5
			Options exercised		-60,676		$	20.67
		Outstanding at March 31, 2014			194,861		$	21.76
		Vested and exercisable at end of period			194,861		$	21.76
Summarizes information about the Company's vested and exercisable stock options outstanding	'
	The following table summarizes information about the Company's vested and exercisable stock options outstanding at March 31, 2014:
								Weighted
								Average			Weighted			Intrinsic
			Range of					Remaining			Average			Value
			Exercise			Number		Contractual			Exercise			of
			Prices			Vested		Life			Price			Options
														(in thousands)
		Vested and exercisable options:
			$12.00			8,536		1.74 years			$	12	$	943
			$12.50 - $15.50			15,000		3.38 years			$	12.85		1,645
			$20.00 - $23.00			140,770		4.41 years			$	21.23		14,256
			$28.00 - $37.27			30,555		4.14 years			$	31.33		2,786
						194,861		4.17 years			$	21.76	$	19,630
Summarizes information about stock-based compensation for stock options	'
	The following table summarizes information about stock-based compensation for stock options for the three months ended March 31, 2014 and 2013:
				Three Months Ended
				March 31,
	(in thousands)					2014			2013
	Stock-based compensation expense from stock options				$	-		$	14
	Income taxes and other information:
		Income tax benefit related to stock options			$	-		$	5
		Deductions in current taxable income related to stock options exercised			$	6,138		$	8,501
Summarizes the assumptions to estimate the fair value of performance units granted	'
	The Company used the following assumptions to estimate the fair value of performance unit awards granted during the three months ended March 31, 2014 and 2013:
					Three Months Ended
					March 31,
					2014			2013
	Risk-free interest rate				0.76%			0.37%
	Range of volatilities				29.2% - 42.2%			31.5% - 45.1%
Summary of the Company's performance unit activity	'
	The following table summarizes the performance unit activity for the three months ended March 31, 2014:
						Number of			Grant Date
						Units (a)			Fair Value
	Performance units:
		Outstanding at December 31, 2013				110,889
			Units granted			139,425		$	139.54
		Outstanding at March 31, 2014				250,314
	(a)	Reflects the amount of performance units granted. The actual payout of shares will be between zero and 300 percent of the performance units granted depending on the Company's performance at the end of the performance period.
Summarizes information about stock-based compensation for the Company's performance unit awards activity under the Plan	'
	The following table summarizes information about stock-based compensation expense for performance units for the three months ended March 31, 2014:
					Three Months Ended
					March 31,
	(in thousands)				2014				2013
	Grant date fair value for awards during the period				$	19,455		$	12,353
	Stock-based compensation expense from performance units				$	2,593		$	993
	Income tax benefit related to performance units				$	975		$	380
Future stock-based compensation expense to be recorded for all the stock-based compensation awards that were outstanding	'
	Future stock-based compensation expense. The following table reflects the future stock-based compensation expense to be recorded for all the stock-based compensation awards that were outstanding at March 31, 2014:
					Restricted			Performance
	(in thousands)				Stock			Units			Total
	Remaining 2014			$	24,473		$	7,952		$	32,425
	2015				18,531			10,639			29,170
	2016				8,136			6,543			14,679
	2017				1,670			-			1,670
	2018				263			-			263
	Thereafter				3			-			3
		Total		$	53,076		$	25,134		$	78,210

Disclosures_about_fair_value_o1

Disclosures about fair value of financial instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Carrying amounts and fair values of the Company's financial instruments	'
					31-Mar-14						31-Dec-13
					Carrying			Fair			Carrying			Fair
	(in thousands)				Value			Value			Value			Value
		Assets:
			Derivative instruments		$	1,627		$	1,627		$	1,556		$	1,556
		Liabilities:
			Derivative instruments		$	88,638		$	88,638		$	67,789		$	67,789
			Credit facility		$	294,650		$	298,722		$	250,000		$	250,770
			7.0% senior notes due 2021		$	600,000		$	661,500		$	600,000		$	660,000
			6.5% senior notes due 2022		$	600,000		$	654,000		$	600,000		$	649,500
			5.5% senior notes due 2022		$	600,000		$	625,500		$	600,000		$	619,500
			5.5% senior notes due 2023		$	1,579,784		$	1,642,975		$	1,580,421		$	1,627,834
Net basis derivative fair values as reported in the consolidated balance sheets	'
	31-Mar-14
						Fair Value Measurements Using															Net
						Quoted Prices													Gross		Fair Value
						in Active					Significant								Amounts		Presented
						Markets for					Other			Significant					Offset in the		in the
						Identical					Observable			Unobservable					Consolidated		Consolidated
						Assets					Inputs			Inputs			Total		Balance		Balance
	(in thousands)					(Level 1)					(Level 2)			(Level 3)			Fair Value		Sheet		Sheet
		Assets
			Current:
				Commodity derivatives			$	-		$	32,599		$	-		$	32,599	$	-31,241	$	1,358
			Noncurrent:
				Commodity derivatives				-			4,334			-			4,334		-4,065		269
		Liabilities
			Current:
				Commodity derivatives				-			-102,065			-			-102,065		31,241		-70,824
			Noncurrent:
				Commodity derivatives				-			-21,879			-			-21,879		4,065		-17,814
		Net derivative instruments					$	-		$	-87,011		$	-		$	-87,011	$	-	$	-87,011
	31-Dec-13
						Fair Value Measurements Using															Net
						Quoted Prices													Gross		Fair Value
						in Active					Significant								Amounts		Presented
						Markets for					Other			Significant					Offset in the		in the
						Identical					Observable			Unobservable					Consolidated		Consolidated
						Assets					Inputs			Inputs			Total		Balance		Balance
	(in thousands)					(Level 1)					(Level 2)			(Level 3)			Fair Value		Sheet		Sheet
		Assets
			Current:
				Commodity derivatives			$	-		$	12,819		$	-		$	12,819	$	-12,229	$	590
			Noncurrent:
				Commodity derivatives				-			5,300			-			5,300		-4,334		966
		Liabilities
			Current:
				Commodity derivatives				-			-65,930			-			-65,930		12,229		-53,701
			Noncurrent:
				Commodity derivatives				-			-18,422			-			-18,422		4,334		-14,088
		Net derivative instruments					$	-		$	-66,233		$	-		$	-66,233	$	-	$	-66,233

Derivative_financial_instrumen1

Derivative financial instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Summarizes the gains and losses reported in earnings related to the commodity and interest rate derivative instruments	'
				Three Months Ended
				March 31,
	(in thousands)				2014			2013
	Loss on derivatives not designated as hedges:
		Oil derivatives		$	-24,220		$	-59,017
		Natural gas derivatives			-11,395			-
			Total loss on derivatives not designated as hedges	$	-35,615		$	-59,017
	The following table represents the Company's cash receipts from (payments on) derivatives reported in the Company's cash flows from investing for the three months ended March 31, 2014 and 2013:
				Three Months Ended
				March 31,
	(in thousands)				2014			2013
	Cash receipts from (payments on) derivatives not designated as hedges:
		Oil derivatives		$	-9,769		$	6,016
		Natural gas derivatives			-5,068			-
			Total cash receipts from (payments on) derivatives not designated as hedges	$	-14,837		$	6,016
				Three Months Ended
				March 31,
	(in thousands)				2014			2013
	Loss on derivatives not designated as hedges:
		Oil derivatives		$	-24,220		$	-59,017
		Natural gas derivatives			-11,395			-
			Total loss on derivatives not designated as hedges	$	-35,615		$	-59,017
	The following table represents the Company's cash receipts from (payments on) derivatives reported in the Company's cash flows from investing for the three months ended March 31, 2014 and 2013:
				Three Months Ended
				March 31,
	(in thousands)				2014			2013
	Cash receipts from (payments on) derivatives not designated as hedges:
		Oil derivatives		$	-9,769		$	6,016
		Natural gas derivatives			-5,068			-
			Total cash receipts from (payments on) derivatives not designated as hedges	$	-14,837		$	6,016
Company's outstanding derivative contracts	'
					First		Second		Third		Fourth
					Quarter		Quarter		Quarter		Quarter		Total
	Oil Swaps: (a)
		2014:00:00
			Volume (Bbl)				4,544,000		4,116,000		3,833,000		12,493,000
			Price per Bbl			$	92.69	$	91.23	$	91.09	$	91.72
		2015:00:00
			Volume (Bbl)		3,428,000		3,264,000		3,123,000		2,997,000		12,812,000
			Price per Bbl	$	87.33	$	86.54	$	86.8	$	86.75	$	86.86
		2016:00:00
			Volume (Bbl)		108,000		108,000		108,000		105,000		429,000
			Price per Bbl	$	88.32	$	88.32	$	88.32	$	88.28	$	88.31
		2017:00:00
			Volume (Bbl)		84,000		84,000		-		-		168,000
			Price per Bbl	$	87	$	87	$	-	$	-	$	87
	Oil Basis Swaps: (b)
		2014:00:00
			Volume (Bbl)				3,458,000		3,956,000		3,680,000		11,094,000
			Price per Bbl			$	-0.72	$	-0.99	$	-0.92	$	-0.88
	Natural Gas Swaps: (c)
		2014:00:00
			Volume (MMBtu)				3,335,000		2,576,000		2,053,000		7,964,000
			Price per MMBtu			$	4.22	$	4.23	$	4.24	$	4.23
		2015:00:00
			Volume (MMBtu)		5,850,000		5,915,000		5,980,000		5,980,000		23,725,000
			Price per MMBtu	$	4.16	$	4.16	$	4.16	$	4.16	$	4.16
	Natural Gas Collars: (d)
		2014:00:00
			Volume (MMBtu)				5,460,000		5,520,000		5,520,000		16,500,000
			Ceiling price per MMBtu			$	4.4	$	4.4	$	4.4	$	4.4
			Floor price per MMBtu			$	3.85	$	3.85	$	3.85	$	3.85
	(a) The index prices for the oil price swaps are based on the NYMEX – West Texas Intermediate ("WTI") monthly average futures price.
	(b) The basis differential price is between Midland – WTI and Cushing – WTI.
	(c) The index prices for the natural gas price swaps are based on the NYMEX – Henry Hub last trading day futures price.
	(d) The index prices for the natural gas collars are based on the El Paso Permian delivery point.

Debt_Tables

Debt (Tables)	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Company's debt	'
						March 31,			December 31,
	(in thousands)					2014			2013
	Credit facility				$	294,650		$	250,000
	7.0% unsecured senior notes due 2021					600,000			600,000
	6.5% unsecured senior notes due 2022					600,000			600,000
	5.5% unsecured senior notes due 2022					600,000			600,000
	5.5% unsecured senior notes due 2023					1,550,000			1,550,000
	Unamortized original issue premium, net					29,784			30,421
		Less: current portion				-			-
			Total long-term debt		$	3,674,434		$	3,630,421
Future interest expense from the 2017 Senior Notes original issue discount	'
	Future benefit to interest expense from original issue premium at March 31, 2014 was as follows:
	(in thousands)
	Remaining 2014			$		1,964
	2015					2,747
	2016					2,900
	2017					3,062
	2018					3,233
	2019					3,413
	Thereafter					12,465
		Total		$		29,784
Principal maturities of debt	'
	Principal maturities of long-term debt. Principal maturities of long-term debt outstanding at March 31, 2014 were as follows:
	(in thousands)
	Remaining 2014			$		-
	2015					-
	2016					294,650
	2017					-
	2018					-
	2019					-
	Thereafter					3,350,000
		Total		$		3,644,650
Interest expense	'
	Interest expense. The following amounts have been incurred and charged to interest expense for the three months ended March 31, 2014 and 2013:
							Three Months Ended
							March 31,
	(in thousands)							2014			2013
	Cash payments for interest						$	44,320		$	43,988
	Amortization of original issue discount (premium)							-637			123
	Amortization of deferred loan origination costs							3,347			3,254
	Net changes in accruals							9,105			4,741
		Total interest expense					$	56,135		$	52,106

Commitments_and_contingencies_

Commitments and contingencies (Tables)	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Summary of the Company's future drilling commitments	'
	The following table summarizes the Company's future drilling commitments at March 31, 2014:
			Payments Due By Period
							Less than		3-Jan		5-Mar		More than
	(in thousands)			Total			1 year		years		years		5 years
	Contractual drilling commitments		$	11,288		$	11,288	$	-	$	-	$	-
Future minimum lease commitments under non-cancellable operating leases	'
	Future minimum lease commitments under non-cancellable operating leases at March 31, 2014 were as follows:
	(in thousands)
	Remaining 2014			$	4,966
	2015				5,546
	2016				4,202
	2017				4,411
	2018				3,928
	2019				3,980
	Thereafter				8,659
		Total		$	35,692

Related_party_transactions_Tab

Related party transactions (Tables)	3 Months Ended
	Mar. 31, 2014
Related Party Transactions [Abstract]	'
Summary of charges incurred with and payments made to the Company's related parties and reported in the consolidated statements of operations	'
		Three Months Ended
		March 31,
	(in thousands)		2014		2013
	Royalties paid to a partnership in which a director has an ownership interest (a)	$	2,802	$	1,340
	Royalties paid to a director and certain officers of the Company (b)	$	97	$	10
	Amounts paid under consulting agreement with Steven L. Beal (c)	$	-	$	60
	Royalties paid on certain properties to a partnership of which a director of the Company is the general partner and owns a 3.5 percent partnership interest.
	Payments made to a director and certain officers who directly own overriding royalty interests in properties owned by the Company.
	On June 30, 2009, Steven L. Beal, the Company's then-president and chief operating officer, retired from such positions. On June 9, 2009, the Company entered into a consulting agreement (the “Consulting Agreement”) with Mr. Beal, under which Mr. Beal began serving as a consultant to the Company on July 1, 2009. During the term of the consulting relationship, Mr. Beal received a consulting fee of $20,000 per month and a monthly reimbursement for his medical and dental coverage costs. In August 2013, the Company and Mr. Beal mutually terminated the Consulting Agreement in exchange for the payment to Mr. Beal of $720,000, which termination and payment were approved by the disinterested members of the Company's Board of Directors.

Net_income_per_share_Tables

Net income per share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]	'
Reconciliation of earnings attributable to common shares, basic and diluted	'
	The following tables reconcile the Company's income from continuing operations, income from discontinued operations and net income attributable to common stockholders to the basic and diluted earnings used to determine the Company's income per share amounts for the three months ended March 31, 2014 and 2013, respectively, under the two-class method:
						Three Months Ended
						31-Mar-14
					Continuing			Discontinued
	(in thousands, except per share amounts)				Operations			Operations		Total
	Income as reported				$	91,307		$	-	$	91,307
	Participating basic earnings					-1,068			-		-1,068
		Basic income attributable to common stockholders				90,239			-		90,239
	Reallocation of participating earnings					4			-		4
		Diluted income attributable to common stockholders			$	90,243		$	-	$	90,243
	Income per common share:
		Basic			$	0.87		$	-	$	0.87
		Diluted			$	0.87		$	-	$	0.87
						Three Months Ended
						31-Mar-13
					Continuing			Discontinued
	(in thousands, except per share amounts)				Operations			Operations		Total
	Income as reported				$	17,559		$	12,534	$	30,093
	Participating basic earnings					-			-		-
		Basic income attributable to common stockholders				17,559			12,534		30,093
	Reallocation of participating earnings					-			-		-
		Diluted income attributable to common stockholders			$	17,559		$	12,534	$	30,093
	Income per common share:
		Basic			$	0.17		$	0.12	$	0.29
		Diluted			$	0.17		$	0.12	$	0.29
reconciliation of the basic weighted average common shares outstanding to diluted weighted average common shares outstanding	'
	The following table is a reconciliation of the basic weighted average common shares outstanding to diluted weighted average common shares outstanding for the three months ended March 31, 2014 and 2013:
					Three Months Ended
					March 31,
	(in thousands)				2014		2013
	Weighted average common shares outstanding:
		Basic			103,949		103,631
			Dilutive common stock options		123		204
			Dilutive restricted stock		-		510
			Dilutive performance units		234		-
		Diluted			104,306		104,345
summary of the common stock options and restricted stock which were not included in the computation of diluted net income per share	'
	The following table is a summary of the common stock options, restricted stock and performance units, which were not included in the computation of diluted net income per share, as inclusion of these items would be antidilutive:
				Three Months Ended
				March 31,
	(in thousands)			2014		2013
	Number of antidilutive common shares:
		Antidilutive restricted stock		46		13
		Antidilutive performance units		-		111

Other_current_liabilities_Tabl

Other current liabilities (Tables)	3 Months Ended
	Mar. 31, 2014
Other Liabilities Disclosure [Abstract]	'
components of the Company's other current liabilities	'
	The following table provides the components of the Company's other current liabilities at March 31, 2014 and December 31, 2013:
					March 31,		December 31,
	(in thousands)				2014		2013
	Other current liabilities:
		Accrued production costs		$	46,553	$	48,196
		Payroll related matters			30,863		28,498
		Accrued interest			79,105		70,000
		Settlements due on derivatives			2,993		1,175
		Asset retirement obligations			4,982		4,481
		Other			6,740		4,250
			Other current liabilities	$	171,236	$	156,600

Subsidiary_guarantors_Tables

Subsidiary guarantors (Tables)	3 Months Ended
	Mar. 31, 2014
Guarantees [Abstract]	'
Condensed Consolidating Balance Sheet	'
	Condensed Consolidating Balance Sheet
	31-Mar-14
				Parent			Subsidiary			Consolidating
	(in thousands)			Issuer			Guarantors			Entries			Total
	ASSETS
	Accounts receivable - related parties		$	6,092,946		$	1,244,197		$	-7,337,143		$	-
	Other current assets			40,628			534,803			-			575,431
	Oil and natural gas properties, net			-			9,167,502			-			9,167,502
	Property and equipment, net			-			116,159			-			116,159
	Investment in subsidiaries			4,135,667			-			-4,135,667			-
	Other long-term assets			69,970			49,106			-			119,076
		Total assets	$	10,339,211		$	11,111,767		$	-11,472,810		$	9,978,168
	LIABILITIES AND EQUITY
	Accounts payable - related parties		$	1,244,197		$	6,092,946		$	-7,337,143		$	-
	Other current liabilities			155,002			783,602			-			938,604
	Other long-term liabilities			1,404,391			99,552			-			1,503,943
	Long-term debt			3,674,434			-			-			3,674,434
	Equity			3,861,187			4,135,667			-4,135,667			3,861,187
		Total liabilities and equity	$	10,339,211		$	11,111,767		$	-11,472,810		$	9,978,168
	Condensed Consolidating Balance Sheet
	31-Dec-13
				Parent			Subsidiary			Consolidating
	(in thousands)			Issuer			Guarantors			Entries			Total
	ASSETS
	Accounts receivable - related parties		$	6,115,554		$	1,261,844		$	-7,377,398		$	-
	Other current assets			39,108			481,767			-			520,875
	Oil and natural gas properties, net			-			8,831,265			-			8,831,265
	Property and equipment, net			-			114,783			-			114,783
	Investment in subsidiaries			3,896,741			-			-3,896,741			-
	Other long-term assets			74,013			50,228			-			124,241
		Total assets	$	10,125,416		$	10,739,887		$	-11,274,139		$	9,591,164
	LIABILITIES AND EQUITY
	Accounts payable - related parties		$	1,261,844		$	6,115,554		$	-7,377,398		$	-
	Other current liabilities			126,461			630,407			-			756,868
	Other long-term liabilities			1,348,741			97,185			-			1,445,926
	Long-term debt			3,630,421			-			-			3,630,421
	Equity			3,757,949			3,896,741			-3,896,741			3,757,949
		Total liabilities and equity	$	10,125,416		$	10,739,887		$	-11,274,139		$	9,591,164
Condensed Consolidating Statement of Operations	'
	Condensed Consolidating Statement of Operations
	Three Months Ended March 31, 2014
				Parent			Subsidiary			Consolidating
	(in thousands)			Issuer			Guarantors			Entries			Total
	Total operating revenues		$	-		$	660,959		$	-		$	660,959
	Total operating costs and expenses			-36,153			-422,574			-			-458,727
		Income (loss) from operations		-36,153			238,385			-			202,232
	Interest expense			-56,135			-			-			-56,135
	Other, net			238,926			541			-238,926			541
		Income before income taxes		146,638			238,926			-238,926			146,638
	Income tax expense			-55,331			-			-			-55,331
		Net income	$	91,307		$	238,926		$	-238,926		$	91,307
	Condensed Consolidating Statement of Operations
	Three Months Ended March 31, 2013
				Parent			Subsidiary			Consolidating
	(in thousands)			Issuer			Guarantors			Entries			Total
	Total operating revenues		$	-		$	472,127		$	-		$	472,127
	Total operating costs and expenses			-59,196			-332,180			-			-391,376
		Income (loss) from continuing operations		-59,196			139,947			-			80,751
	Interest expense			-52,106			-			-			-52,106
	Other, net			160,201			-109			-160,201			-109
		Income from continuing operations before income taxes		48,899			139,838			-160,201			28,536
	Income tax expense			-10,977			-			-			-10,977
		Income from continuing operations		37,922			139,838			-160,201			17,559
	Income (loss) from discontinued operations, net of tax			-7,829			20,363			-			12,534
		Net income	$	30,093		$	160,201		$	-160,201		$	30,093
Condensed Consolidating Statement of Cash Flows	'
	Condensed Consolidating Statement of Cash Flows
	Three Months Ended March 31, 2014
					Parent			Subsidiary			Consolidating
	(in thousands)				Issuer			Guarantors			Entries			Total
	Net cash flows provided by (used in) operating activities			$	-30,312		$	506,292		$	-		$	475,980
	Net cash flows used in investing activities				-14,837			-559,859			-			-574,696
	Net cash flows provided by financing activities				45,149			53,567			-			98,716
		Net decrease in cash and cash equivalents			-			-			-			-
		Cash and cash equivalents at beginning of period			-			21			-			21
		Cash and cash equivalents at end of period		$	-		$	21		$	-		$	21
	Condensed Consolidating Statement of Cash Flows
	Three Months Ended March 31, 2013
					Parent			Subsidiary			Consolidating
	(in thousands)				Issuer			Guarantors			Entries			Total
	Net cash flows provided by (used in) operating activities			$	-171,843		$	391,514		$	-		$	219,671
	Net cash flows provided by (used in) investing activities				6,016			-408,145			-			-402,129
	Net cash flows provided by financing activities				165,827			14,725			-			180,552
		Net decrease in cash and cash equivalents			-			-1,906			-			-1,906
		Cash and cash equivalents at beginning of period			-			2,880			-			2,880
		Cash and cash equivalents at end of period		$	-		$	974		$	-		$	974

Subsequent_events_Tables

Subsequent events (Tables)	3 Months Ended
	Mar. 31, 2014
Subsequent Events [Abstract]	'
New commodity derivative contracts	'
	New commodity derivative contracts. After March 31, 2014, the Company entered into the following oil price swaps, oil basis swaps and natural gas basis swaps to hedge additional amounts of the Company's estimated future production:
					First		Second		Third		Fourth
					Quarter		Quarter		Quarter		Quarter		Total
	Oil Swaps: (a)
		2014:00:00
			Volume (Bbl)				440,000		455,000		340,000		1,235,000
			Price per Bbl			$	99.9	$	99.53	$	99.12	$	99.55
		2015:00:00
			Volume (Bbl)		360,000		360,000		210,000		210,000		1,140,000
			Price per Bbl	$	91.5	$	91.5	$	90.76	$	90.76	$	91.23
	Oil Basis Swaps: (b)
		2014:00:00
			Volume (Bbl)				-		-		276,000		276,000
			Price per Bbl			$	-	$	-	$	-3	$	-3
		2015:00:00
			Volume (Bbl)		270,000		273,000		-		-		543,000
			Price per Bbl	$	-3	$	-3	$	-	$	-	$	-3
	Natural Gas Basis Swaps: (c)
		2014:00:00
			Volume (MMBtu)				1,220,000		1,840,000		1,840,000		4,900,000
			Price per MMBtu			$	-0.11	$	-0.11	$	-0.11	$	-0.11
	(a)	The index prices for the oil price swaps are based on the NYMEX – WTI monthly average futures price.
	(b)	The basis differential price is between Midland – WTI and Cushing – WTI.
	(c)	The basis differential price is between the El Paso Permian delivery point and NYMEX – Henry Hub delivery point.
					First		Second		Third		Fourth
					Quarter		Quarter		Quarter		Quarter		Total
	Oil Swaps: (a)
		2014:00:00
			Volume (Bbl)				440,000		455,000		340,000		1,235,000
			Price per Bbl			$	99.9	$	99.53	$	99.12	$	99.55
		2015:00:00
			Volume (Bbl)		360,000		360,000		210,000		210,000		1,140,000
			Price per Bbl	$	91.5	$	91.5	$	90.76	$	90.76	$	91.23
	Oil Basis Swaps: (b)
		2014:00:00
			Volume (Bbl)				-		-		276,000		276,000
			Price per Bbl			$	-	$	-	$	-3	$	-3
		2015:00:00
			Volume (Bbl)		270,000		273,000		-		-		543,000
			Price per Bbl	$	-3	$	-3	$	-	$	-	$	-3
	Natural Gas Basis Swaps: (c)
		2014:00:00
			Volume (MMBtu)				1,220,000		1,840,000		1,840,000		4,900,000
			Price per MMBtu			$	-0.11	$	-0.11	$	-0.11	$	-0.11
	(a)	The index prices for the oil price swaps are based on the NYMEX – WTI monthly average futures price.
	(b)	The basis differential price is between Midland – WTI and Cushing – WTI.
	(c)	The basis differential price is between the El Paso Permian delivery point and NYMEX – Henry Hub delivery point.

Supplementary_information_Tabl

Supplementary information (Tables)	3 Months Ended
	Mar. 31, 2014
Oil and Gas Exploration and Production Industries Disclosures [Abstract]	'
Capitalized costs	'
				March 31,		December 31,
	(in thousands)			2014		2013
	Oil and natural gas properties:
		Proved		$	10,708,779	$	10,182,953
		Unproved			1,059,636		1,032,420
		Less: accumulated depletion			-2,600,913		-2,384,108
			Net capitalized costs for oil and natural gas properties	$	9,167,502	$	8,831,265
costs incurred for oil and natural gas producing activities	'
				Three Months Ended
				March 31,
	(in thousands)			2014		2013
	Property acquisition costs:
		Proved		$	20,490	$	1,885
		Unproved			24,688		27,896
	Exploration				324,497		266,690
	Development				211,679		174,722
		Total costs incurred for oil and natural gas properties		$	581,354	$	471,193
	(a)	The costs incurred for oil and natural gas producing activities includes the following amounts of asset retirement obligations:
				Three Months Ended
				March 31,
		(in thousands)		2014		2013
		Exploration costs		$	558	$	734
		Development costs			965		1,530
			Total asset retirement obligations	$	1,523	$	2,264

Recovered_Sheet1

Summary Of Significant Accounting Policies (Narrative) (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Disclosure Summary Of Significant Accounting Policies Narrative [Abstract]	'	'	'
Deferred loan costs	$69,701,000	'	$73,048,000
Accumulated amortization	52,100,000	'	48,700,000
Estimated economic life of gross operating rights in years	'25 years	'	'
Fees related to operation of jointly owned oil and natural gas properties	$5,100,000	$4,200,000	'

Recovered_Sheet2

Summary Of Significant Accounting Policies (Future Amortization Expense Of Deferred Loan Costs) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Disclosure Summary Of Significant Accounting Policies Future Amortization Expense Of Deferred Loan Costs [Abstract]	'
Remaining 2014	$10,156
2015	13,820
2016	8,476
2017	5,994
2018	6,376
2019	6,784
Thereafter	18,095
Total	$69,701

Recovered_Sheet3

Summary Of Significant Accounting Policies (Gross And Net Intangible Assets) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Disclosure Summary Of Significant Accounting Policies Gross And Net Intangible Assets [Abstract]	'	'
Gross intangible - operating rights	$36,557	$36,557
Accumulated amortization	-8,307	-7,942
Net intangible - operating rights	$28,250	$28,615

Summary_Of_Significant_Account3

Summary Of Significant Accounting Policies (Amortization Expense) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Disclosure Summary Of Significant Accounting Policies Amortization Expense [Abstract]	'	'
Amortization expense	$365	$365

Summary_Of_Significant_Account4

Summary Of Significant Accounting Policies (Estimated Future Aggregate Amortization Expense) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Disclosure Summary Of Significant Accounting Policies Estimated Future Aggregate Amortization Expense [Abstract]	'	'
Remaining 2014	$1,096	'
2015	1,461	'
2016	1,461	'
2017	1,461	'
2018	1,461	'
2019	1,461	'
Thereafter	19,849	'
Total	$28,250	$28,615

Exploratory_Well_Costs_Capital

Exploratory Well Costs (Capitalized Exploratory Well Activity) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Disclosure Exploratory Well Costs Capitalized Exploratory Well Activity [Abstract]	'
Beginning capitalized exploratory well costs	$144,504
Additions to exploratory well costs pending the determination of proved reserves	134,660
Reclassifications due to determination of proved reserves	-86,904
Exploratory well costs charged to expense	-19,286
Ending capitalized exploratory well costs	$172,974

Exploratory_Well_Costs_Aging_O

Exploratory Well Costs (Aging Of Capitalized Exploratory Well Costs Based On The Date Of Drilling) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Number	Number
Disclosure Exploratory Well Costs Aging Of Capitalized Exploratory Well Costs Based On The Date Of Drilling [Abstract]	'	'
Capitalized exploratory well costs that have been capitalized for a period of one year or less	$152,891	$122,753
Capitalized exploratory well costs that have been capitalized for a period greater than one year	20,083	21,751
Total capitalized exploratory well costs	$172,974	$144,504
Projects that have Exploratory Well Costs that have been Capitalized for Period Greater than One Year, Number of Projects	12	10

Exploratory_Well_Costs_Narrati

Exploratory Well Costs (Narrative) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Oil And Gas In Process Activities [Line Items]	'	'
Capitalized Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year	$20,083	$21,751
Southern Delaware Basin Projects [Member]	'	'
Oil And Gas In Process Activities [Line Items]	'	'
Capitalized Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year	8,900	'
Other Projects [Member]	'	'
Oil And Gas In Process Activities [Line Items]	'	'
Capitalized Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year	4,900	'
OBO Projects [Member]	'	'
Oil And Gas In Process Activities [Line Items]	'	'
Capitalized Exploratory Well Costs That Have Been Capitalized For Period Greater Than One Year	$6,200	'

Asset_Retirement_Obligations_S

Asset Retirement Obligations (Schedule Of Asset Retirement Obligation Transactions) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Disclosure Asset Retirement Obligations Schedule Of Asset Retirement Obligation Transactions [Abstract]	'	'
Asset retirement obligations, beginning of period	$101,593	$86,261
Liabilities incurred from new wells	995	1,592
Liabilities assumed in acquisitions	200	161
Accretion expense	1,671	1,394
Liabilities settled upon plugging and abandoning wells	-524	-1,157
Revision of estimates	528	672
Asset retirement obligations, end of period	$104,463	$88,923

Incentive_Plans_Narrative_Deta

Incentive Plans (Narrative) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Defined contribution and plans employers contribution	$1.90	$1.20
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$6.10	$8.50
Performance unit awards vesting period	'3 years	'
Plan 401 k [Member]	'	'
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Defined contribution plan employer's contribution match percentage	100.00%	'
Defined contribution plan, employee contribution	10.00%	'

Incentive_Plans_Schedule_Of_Re

Incentive Plans (Schedule Of Restricted Stock Awards Activity) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Disclosure Incentive Plans Schedule Of Restricted Stock Awards Activity [Abstract]	'
Outstanding at beginning of period	1,216,449
Shares granted	134,989
Shares cancelled / forfeited	-20,535
Lapse of restrictions	-117,481
Outstanding at end of period	1,213,422
Shares Granted - Grant Date Value Per Share	$108.42

Incentive_Plans_Summary_Inform

Incentive Plans (Summary Information For Stock-Based Compensation For Restricted Stock Awards) (Detail) (Restricted Stock [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Restricted Stock [Member]	'	'
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]	'	'
Grant date fair value for awards during the period	$14,636	$11,979	[1]
Stock-based compensation expense from restricted stock	8,839	5,760
Income tax benefit related to restricted stock	2,915	2,202
Deductions in current taxable income related to restricted stock vestings	$12,663	$9,790
[1]	(a)The three months ended March 31, 2013 includes the effects of $1 million due to modifications of certain stock-based awards.

Incentive_Plans_Schedule_Of_St

Incentive Plans (Schedule Of Stock Option Awards Activity) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Disclosure Incentive Plans Schedule Of Stock Option Awards Activity [Abstract]	'
Outstanding at beginning of period (Shares)	255,537
Options exercised (Shares)	-60,676
Outstanding at end of period (Shares)	194,861
Exercisable at end of period (Shares)	194,861
Outstanding at beginning of period	$21.50
Options exercised	$20.67
Outstanding at end of period	$21.76
Exercisable at end of Period - Weighted average exercise price	$21.76

Incentive_Plans_Summary_Inform1

Incentive Plans (Summary Information For Vested And Exercisable Stock Options Outstanding) (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]	'
Vested at end of period - Weighted average exercise price	$21.76
Exercisable at end of period (Shares)	194,861
Exercisable Weighted Average Remaining Contractual Life	'4 years 2 months
Exercisable at end of Period - Weighted average exercise price	$21.76
Exercisable Intrinsic Value	$19,630
Range Two [Member]	'
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]	'
Exercise price, Lower range	$12
Exercisable at end of period (Shares)	8,536
Exercisable Weighted Average Remaining Contractual Life	'1 year 9 months
Exercisable at end of Period - Weighted average exercise price	$12
Exercisable Intrinsic Value	943
Range Three [Member]	'
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]	'
Exercise price, Lower range	$12.50
Exercise price, Upper range	$15.50
Exercisable at end of period (Shares)	15,000
Exercisable Weighted Average Remaining Contractual Life	'3 years 5 months
Exercisable at end of Period - Weighted average exercise price	$12.85
Exercisable Intrinsic Value	1,645
Range Four [Member]	'
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]	'
Exercise price, Lower range	$20
Exercise price, Upper range	$23
Exercisable at end of period (Shares)	140,770
Exercisable Weighted Average Remaining Contractual Life	'4 years 5 months
Exercisable at end of Period - Weighted average exercise price	$21.23
Exercisable Intrinsic Value	14,256
Range Five [Member]	'
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]	'
Exercise price, Lower range	$28
Exercise price, Upper range	$37.27
Exercisable at end of period (Shares)	30,555
Exercisable Weighted Average Remaining Contractual Life	'4 years 2 months
Exercisable at end of Period - Weighted average exercise price	$31.33
Exercisable Intrinsic Value	$2,786

Incentive_Plans_Summary_Inform2

Incentive Plans (Summary Information For Stock-Based Compensation For Stock Options) (Detail) (Stock Options [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Stock Options [Member]	'	'
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]	'	'
Stock-based compensation expense from stock options	$0	$14
Income tax benefit related to stock options	0	5
Deductions in current taxable income related to stock options exercised	$6,138	$8,501

Incentive_Plans_Summary_Of_Ass

Incentive Plans (Summary Of Assumptions To Estimate Fair Value of Performance Unit Awards) (Detail)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Disclosure Incentive Plans Schedule Of Performance Unit Awards Fair Value Assumptions [Abstract]	'	'
Risk-free interest rate	0.76%	0.37%
Volatility assumption - minimum	29.20%	31.50%
Volatility assumption - maximum	42.20%	45.10%

Incentive_Plans_Schedule_Of_Pe

Incentive Plans (Schedule Of Performance Unit Awards Activity) (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014		Dec. 31, 2013
Disclosure Incentive Plans Schedule Of Performance Unit Awards Activity [Abstract]	'		'
Performance units outstanding at beginning of period (Shares)	250,314	[1]	110,889	[1]
Units granted	139,425	[1]	'
Performance units outstanding at end of period (Shares)	250,314	[1]	110,889	[1]
Shares Granted - Grant Date Fair Value - Performance Units	$139.54		'
[1]	Reflects the amount of performance units granted. The actual payout of shares will be between zero and 300 percent of the performance units granted depending on the Company's performance at the end of the performance period.

Incentive_Plans_Summary_Inform3

Incentive Plans (Summary Information For Stock-Based Compensation For Performance Units) (Detail) (Performance Shares [Member], Officer And Director Grants [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Performance Shares [Member] | Officer And Director Grants [Member]	'	'
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]	'	'
Grant date fair value for awards during the period	$19,455	$12,353
Allocated Share Based Compensation Expense	2,593	993
Employee Service Share Based Compensation Tax Benefit From Compensation Expense	$975	$380

Incentive_Plans_Summary_For_Fu

Incentive Plans (Summary For Future Stock-Based Compensation Expense) (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]	'
Remaining 2014	$32,425
2015	29,170
2016	14,679
2017	1,670
2018	263
Thereafter	3
Total	78,210
Restricted Stock [Member]	'
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]	'
Remaining 2014	24,473
2015	18,531
2016	8,136
2017	1,670
2018	263
Thereafter	3
Total	53,076
Performance Shares [Member]	'
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]	'
Remaining 2014	7,952
2015	10,639
2016	6,543
2017	0
2018	0
Thereafter	0
Total	$25,134

Recovered_Sheet4

Disclosures About Fair Value Of Financial Instruments (Carrying Amounts And Fair Values Of The Company's Financial Instruments) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Credit facility	$294,650	$250,000
Seven Point Zero Percent Unsecured Senior Notes [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	600,000	600,000
Six Point Five Percent Unsecured Senior Notes [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	600,000	600,000
Five Point Five Percent Unsecured Senior Notes Due Twenty Twenty Three [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	1,550,000	1,550,000
Carrying Reported Amount Fair Value Disclosure [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Derivative instruments, Assets	1,627	1,556
Derivative instruments, Liabilities	88,638	67,789
Credit facility	294,650	250,000
Carrying Reported Amount Fair Value Disclosure [Member] | Seven Point Zero Percent Unsecured Senior Notes [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	600,000	600,000
Carrying Reported Amount Fair Value Disclosure [Member] | Six Point Five Percent Unsecured Senior Notes [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	600,000	600,000
Carrying Reported Amount Fair Value Disclosure [Member] | Five Piont Five Percent Unsecured Senior Notes [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	600,000	600,000
Carrying Reported Amount Fair Value Disclosure [Member] | Five Point Five Percent Unsecured Senior Notes Due Twenty Twenty Three [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	1,579,784	1,580,421
Portion At Fair Value Fair Value Disclosure [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Derivative instruments, Assets	1,627	1,556
Derivative instruments, Liabilities	88,638	67,789
Credit facility	298,722	250,770
Portion At Fair Value Fair Value Disclosure [Member] | Seven Point Zero Percent Unsecured Senior Notes [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	661,500	660,000
Portion At Fair Value Fair Value Disclosure [Member] | Six Point Five Percent Unsecured Senior Notes [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	654,000	649,500
Portion At Fair Value Fair Value Disclosure [Member] | Five Piont Five Percent Unsecured Senior Notes [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	625,500	619,500
Portion At Fair Value Fair Value Disclosure [Member] | Five Point Five Percent Unsecured Senior Notes Due Twenty Twenty Three [Member]	'	'
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]	'	'
Unsecured senior notes	$1,642,975	$1,627,834

Recovered_Sheet5

Disclosures About Fair Value Of Financial Instruments (Company's Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]	'	'
Current derivative contracts, assets	$1,358	$590
Noncurrent derivative contracts, assets	269	966
Current derivative contracts, liabilities	-70,824	-53,701
Noncurrent derivative contracts, liabilities	-17,814	-14,088
Net derivative instruments	-87,011	-66,233
Fair Value Inputs Level 1 [Member]	'	'
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]	'	'
Current derivative contracts, assets	0	0
Noncurrent derivative contracts, assets	0	0
Current derivative contracts, liabilities	0	0
Noncurrent derivative contracts, liabilities	0	0
Net derivative instruments	0	0
Fair Value Inputs Level 2 [Member]	'	'
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]	'	'
Current derivative contracts, assets	32,599	12,819
Noncurrent derivative contracts, assets	4,334	5,300
Current derivative contracts, liabilities	-102,065	-65,930
Noncurrent derivative contracts, liabilities	-21,879	-18,422
Net derivative instruments	-87,011	-66,233
Fair Value Inputs Level 3 [Member]	'	'
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]	'	'
Current derivative contracts, assets	0	0
Noncurrent derivative contracts, assets	0	0
Current derivative contracts, liabilities	0	0
Noncurrent derivative contracts, liabilities	0	0
Net derivative instruments	0	0
Estimate Of Fair Value Fair Value Disclosure [Member]	'	'
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]	'	'
Current derivative contracts, assets	32,599	12,819
Noncurrent derivative contracts, assets	4,334	5,300
Current derivative contracts, liabilities	-102,065	-65,930
Noncurrent derivative contracts, liabilities	-21,879	-18,422
Net derivative instruments	-87,011	-66,233
Gross Amounts Offset in Consolidated Balance Sheet [Member]	'	'
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]	'	'
Current derivative contracts, assets	-31,241	-12,229
Noncurrent derivative contracts, assets	-4,065	-4,334
Current derivative contracts, liabilities	31,241	12,229
Noncurrent derivative contracts, liabilities	4,065	4,334
Net derivative instruments	$0	$0

Disclosures_About_Fair_Value_O2

Disclosures About Fair Value Of Financial Instruments (Fair Value Derivative Instruments) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current:(b)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, current	$1,358	$590
Noncurrent:(c)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, noncurrent	269	966
Current:(b)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, current	-70,824	-53,701
Noncurrent:(c)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, noncurrent	-17,814	-14,088
Net financial assets (liabilities)	-87,011	-66,233
Fair Value Inputs Level 1 [Member]	'	'
Current:(b)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, current	0	0
Noncurrent:(c)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, noncurrent	0	0
Current:(b)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, current	0	0
Noncurrent:(c)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, noncurrent	0	0
Net financial assets (liabilities)	0	0
Fair Value Inputs Level 2 [Member]	'	'
Current:(b)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, current	32,599	12,819
Noncurrent:(c)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, noncurrent	4,334	5,300
Current:(b)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, current	-102,065	-65,930
Noncurrent:(c)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, noncurrent	-21,879	-18,422
Net financial assets (liabilities)	-87,011	-66,233
Fair Value Inputs Level 3 [Member]	'	'
Current:(b)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, current	0	0
Noncurrent:(c)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, noncurrent	0	0
Current:(b)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, current	0	0
Noncurrent:(c)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, noncurrent	0	0
Net financial assets (liabilities)	0	0
Estimate Of Fair Value Fair Value Disclosure [Member]	'	'
Current:(b)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, current	32,599	12,819
Noncurrent:(c)	'	'
Fair value assets measured on recurring basis, derivative financial instruments assets, noncurrent	4,334	5,300
Current:(b)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, current	-102,065	-65,930
Noncurrent:(c)	'	'
Fair value liabilities measured on recurring basis, derivative financial instruments liabilities, noncurrent	-21,879	-18,422
Net financial assets (liabilities)	($87,011)	($66,233)

Recovered_Sheet6

Derivative Financial Instruments (Gains And Losses Reported In Earnings Related To The Commodity And Interest Rate Derivative Instruments) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Derivative Financial Instruments Gains And Losses Reported In Earnings Related To Commodity And Interest Rate Derivative Instruments [Line Items]	'	'
Cash (payments on) receipts from derivatives not designated as hedges	$14,837	($6,016)
Mark-to-market gain (loss)	-35,615	-59,017
Oil Commodity Derivative [Member]	'	'
Derivative Financial Instruments Gains And Losses Reported In Earnings Related To Commodity And Interest Rate Derivative Instruments [Line Items]	'	'
Cash (payments on) receipts from derivatives not designated as hedges	-9,769	6,016
Mark-to-market gain (loss)	-24,220	-59,017
Natural Gas Commodity Derivative [Member]	'	'
Derivative Financial Instruments Gains And Losses Reported In Earnings Related To Commodity And Interest Rate Derivative Instruments [Line Items]	'	'
Cash (payments on) receipts from derivatives not designated as hedges	-5,068	0
Mark-to-market gain (loss)	($11,395)	$0

Recovered_Sheet7

Derivative Financial Instruments (Outstanding Commodity Derivative Contracts) (Detail)	3 Months Ended								12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2014
	bbl		bbl		bbl		bbl		bbl
Oil Swaps [Member]	'		'		'		'		'
Derivative [Line Items]	'		'		'		'		'
Volume (Bbl/MMBtu) - Current Year	3,833,000	[1]	4,116,000	[1]	4,544,000	[1]	'		12,493,000	[1]
Price per Bbl/MMBtu - Current Year	91.09	[1]	91.23	[1]	92.69	[1]	'		91.72	[1]
Volume (Bbl/MMBtu) - Year One	2,997,000	[1]	3,123,000	[1]	3,264,000	[1]	3,428,000	[1]	12,812,000	[1]
Price per Bbl/MMBtu - Year One	86.75	[1]	86.8	[1]	86.54	[1]	87.33	[1]	86.86	[1]
Volume (Bbl/MMBtu) - Year Two	105,000	[1]	108,000	[1]	108,000	[1]	108,000	[1]	429,000	[1]
Price per Bbl/MMBtu - Year Two	88.28	[1]	88.32	[1]	88.32	[1]	88.32	[1]	88.31	[1]
Volume (Bbl/MMBtu) - Year Three	0	[1]	0	[1]	84,000	[1]	84,000	[1]	168,000	[1]
Price per Bbl/MMBtu - Year Three	0	[1]	0	[1]	87	[1]	87	[1]	87	[1]
Oil Basis Swaps [Member]	'		'		'		'		'
Derivative [Line Items]	'		'		'		'		'
Volume (Bbl/MMBtu) - Current Year	3,680,000	[2]	3,956,000	[2]	3,458,000	[2]	'		11,094,000	[2]
Price per Bbl/MMBtu - Current Year	-0.92	[2]	-0.99	[2]	-0.72	[2]	'		-0.88	[2]
Natural Gas Swap [Member]	'		'		'		'		'
Derivative [Line Items]	'		'		'		'		'
Volume (Bbl/MMBtu) - Current Year	2,053,000	[3]	2,576,000	[3]	3,335,000	[3]	'		7,964,000	[3]
Price per Bbl/MMBtu - Current Year	4.24	[3]	4.23	[3]	4.22	[3]	'		4.23	[3]
Volume (Bbl/MMBtu) - Year One	5,980,000	[3]	5,980,000	[3]	5,915,000	[3]	5,850,000	[3]	23,725,000	[3]
Price per Bbl/MMBtu - Year One	4.16	[3]	4.16	[3]	4.16	[3]	4.16	[3]	4.16	[3]
Natural Gas Collars [Member]	'		'		'		'		'
Derivative [Line Items]	'		'		'		'		'
Volume (Bbl/MMBtu) - Current Year	5,520,000	[4]	5,520,000	[4]	5,460,000	[4]	'		16,500,000	[4]
Natural Gas Collars [Member] | Minimum [Member]	'		'		'		'		'
Derivative [Line Items]	'		'		'		'		'
Price per Bbl/MMBtu - Current Year	3.85	[4]	3.85	[4]	3.85	[4]	'		3.85	[4]
Natural Gas Collars [Member] | Maximum [Member]	'		'		'		'		'
Derivative [Line Items]	'		'		'		'		'
Price per Bbl/MMBtu - Current Year	4.4	[4]	4.4	[4]	4.4	[4]	'		4.4	[4]
[1]	(a) The index prices for the oil price swaps are based on the NYMEX b West Texas Intermediate ("WTI") monthly average futures price.
[2]	(b) The basis differential price is between Midland b WTI and Cushing b WTI.
[3]	(c) The index prices for the natural gas price swaps are based on the NYMEX b Henry Hub last trading day futures price.
[4]	(d) The index prices for the natural gas collars are based on the El Paso Permian delivery point.

Debt_Summary_Of_LongTerm_Debt_

Debt (Summary Of Long-Term Debt) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'	'
Credit facility	$294,650	$250,000
Unamortized original issue discount, net	29,784	30,421
Less: current portion	0	0
Total long-term debt	3,674,434	3,630,421
7.0% senior notes due 2021	'	'
Debt Instrument [Line Items]	'	'
Unsecured senior notes	600,000	600,000
6.5% senior notes due 2022	'	'
Debt Instrument [Line Items]	'	'
Unsecured senior notes	600,000	600,000
5.5% unsecured senior notes due 2022	'	'
Debt Instrument [Line Items]	'	'
Unsecured senior notes	600,000	600,000
5.5% unsecured senior notes due 2023	'	'
Debt Instrument [Line Items]	'	'
Unsecured senior notes	$1,550,000	$1,550,000

Debt_Narrative_Detail

Debt (Narrative) (Detail) (USD $)	3 Months Ended	4 Months Ended
In Billions, unless otherwise specified	Mar. 31, 2014	9-May-14
Debt Disclosure [Line Items]	'	'
Line of credit maturity date	25-Apr-16	9-May-19
Aggregate maximum borrowing base	$3	$3.25
Aggregate lender commitments	$2.50	'
Line of credit start date	'	9-May-14

Debt_Future_Interest_Expense_F

Debt (Future Interest Expense From Original Issue Discount On Senior Notes) (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Disclosure Debt Future Interest Expense From Original Issue Discount On Senior Notes [Abstract]	'
Remaining 2014	$1,964
2015	2,747
2016	2,900
2017	3,062
2018	3,233
2019	3,413
Thereafter	12,465
Total	$29,784

Debt_Principal_Maturities_Of_D

Debt (Principal Maturities Of Debt) (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Disclosure Debt Principal Maturities Of Debt [Abstract]	'
Remaining 2014	$0
2015	0
2016	294,650
2017	0
2018	0
2019	0
Thereafter	3,350,000
Total	$3,644,650

Debt_Summary_Of_Interest_Expen

Debt (Summary Of Interest Expense) (Detail) (USD $)	3 Months Ended		4 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	9-May-14
Disclosure Debt Summary Of Interest Expense [Abstract]	'	'	'
Cash payments for interest	$44,320,000	$43,988,000	'
Amortization of original issue discount (premium)	-637,000	123,000	'
Amortization of deferred loan origination costs	3,347,000	3,254,000	'
Write-off of deferred loan origination costs and original issue premium	'	'	4,300,000
Net changes in accruals	9,105,000	4,741,000	'
Interest costs incurred	56,135,000	52,106,000	'
Total interest expense	$56,135,000	$52,106,000	'

Recovered_Sheet8

Commitments And Contingencies (Narrative) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Commitments [Line Items]	'	'
Annual officers' salaries	$7	'
Operating leases, lease payments	1.7	1.2
Accrued Exposure	$12.70	$12.20

Commitments_And_Contingencies_1

Commitments And Contingencies (Future Drilling Commitments) (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Disclosure Commitments And Contingencies Future Drilling Commitments [Abstract]	'
Total	$11,288
Paymets Less than 1 year	11,288
Payments Due By Period 1 - 3 years	0
Payments Due By Period 3 - 5 years	0
More than 5 years	$0

Commitments_And_Contingencies_2

Commitments And Contingencies (Future Minimum Lease Commitments Under Non-Cancellable Operating Leases) (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Disclosure Commitments And Contingencies Future Minimum Lease Commitments Under Non Cancellable Operating Leases [Abstract]	'
Remaining 2014	$4,966
2015	5,546
2016	4,202
2017	4,411
2018	3,928
2019	3,980
Thereafter	8,659
Total	$35,692

Income_Taxes_Narrative_Detail

Income Taxes (Narrative) (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 13, 2018	Dec. 31, 2013
Disclosure Income Taxes Narrative [Abstract]	'	'	'	'
Effective tax rate	37.70%	38.50%	'	'
New Mexico State Tax Rate	'	'	5.90%	7.60%

Related_Party_Transactions_Sch

Related Party Transactions (Schedule Of Related Party Transactions) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Related Party Transaction [Line Items]	'		'
Ownership interest in system	3.50%		'
Payment To Mutually Terminate Consulting Agreement	$720,000		'
Partnership (Director Ownership Interest) [Member]	'		'
Related Party Transaction [Line Items]	'		'
Royalty interest paid	2,802,000	[1]	1,340,000	[1]
Director and Certain Officers [Member]	'		'
Related Party Transaction [Line Items]	'		'
Royalty interest paid	97,000	[2]	10,000	[2]
Former President And Chief Operating Officer [Member]	'		'
Related Party Transaction [Line Items]	'		'
Royalty interest paid	0	[3]	60,000	[3]
Consulting fee per month	$20,000		'
[1]	Royalties paid on certain properties to a partnership of which a director of the Company is the general partner and owns a 3.5 percent partnership interest.
[2]	Payments made to a director and certain officers who directly own overriding royalty interests in properties owned by the Company.
[3]	On JuneB 30, 2009, Steven L. Beal, the Companybs then-president and chief operating officer, retired from such positions.B On JuneB 9, 2009, the Company entered into a consulting agreement (the bConsulting Agreementb) with Mr.B Beal, under which Mr.B Beal began serving as a consultant to the Company on JulyB 1, 2009. During the term of the consulting relationship, Mr. Beal received a consulting fee of $20,000 per month and a monthly reimbursement for his medical and dental coverage costs. In August 2013, the Company and Mr. Beal mutually terminated the Consulting Agreement in exchange for the payment to Mr. Beal of $720,000, which termination and payment were approved by the disinterested members of the Companybs Board of Directors.

Discontinued_Operations_Narrat

Discontinued Operations (Narrative) (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2012
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]	'	'	'
Approximate discontinued operation disposal sale price	'	'	$503,100,000
Adjustment to gain (loss) related to discontinued operations	'	20,400,000	'
Discontinued Operation Tax Effect Of Discontinued Operation	'	7,900,000	'
Income Loss From Discontinued Operations Net Of Tax	$0	$12,534,000	'

Net_Income_Per_Share_Reconcili

Net Income Per Share (Reconciliation Of Earnings Attributable To Common Shares Basic And Diluted) (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]	'	'
Income (loss) as reported	$91,307	$30,093
Participating basic earnings	-1,068	0
Basic net income (loss) attributable to common stockholders	90,239	30,093
Reallocation of participating earnings	4	0
Diluted net income (loss) attributable to common stockholders	90,243	30,093
Basic	$0.87	$0.29
Diluted	$0.87	$0.29
Segment, Continuing Operations [Member]	'	'
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]	'	'
Income (loss) as reported	91,307	17,559
Participating basic earnings	-1,068	0
Basic net income (loss) attributable to common stockholders	90,239	17,559
Reallocation of participating earnings	4	0
Diluted net income (loss) attributable to common stockholders	90,243	17,559
Basic	$0.87	$0.17
Diluted	$0.87	$0.17
Segment, Discontinued Operations [Member]	'	'
Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]	'	'
Income (loss) as reported	0	12,534
Participating basic earnings	0	0
Basic net income (loss) attributable to common stockholders	0	12,534
Reallocation of participating earnings	0	0
Diluted net income (loss) attributable to common stockholders	$0	$12,534
Basic	$0	$0.12
Diluted	$0	$0.12

Net_Income_Per_Share_Reconcili1

Net Income Per Share (Reconciliation Of The Weighted Average Common Shares Outstanding) (Detail)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reconciliation Of Basic Weighted Average Common Shares Outstanding To Diluted Weighted Average Common Shares Outstanding [Line Items]	'	'
Basic	103,949	103,631
Diluted	104,306	104,345
Stock Options [Member]	'	'
Reconciliation Of Basic Weighted Average Common Shares Outstanding To Diluted Weighted Average Common Shares Outstanding [Line Items]	'	'
Dilutive shares	123	204
Restricted Stock [Member]	'	'
Reconciliation Of Basic Weighted Average Common Shares Outstanding To Diluted Weighted Average Common Shares Outstanding [Line Items]	'	'
Dilutive shares	0	510
Performance Shares [Member]	'	'
Reconciliation Of Basic Weighted Average Common Shares Outstanding To Diluted Weighted Average Common Shares Outstanding [Line Items]	'	'
Dilutive shares	234	0

Net_Income_Per_Share_Summary_O

Net Income Per Share (Summary Of The Common Stock Options And Restricted Stock) (Detail)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Restricted Stock [Member]	'	'
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]	'	'
Antidilutive common shares	46	13
Performance Shares [Member]	'	'
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]	'	'
Antidilutive common shares	0	111

Other_Current_Liabilities_Sche

Other Current Liabilities (Schedule Of Other Current Liabilities) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Other Liabilities Disclosure [Abstract]	'	'
Accrued production costs	$46,553	$48,196
Payroll related matters	30,863	28,498
Accrued interest	79,105	70,000
Settlements due on derivatives	2,993	1,175
Asset retirement obligations	4,982	4,481
Other	6,740	4,250
Other current liabilities	$171,236	$156,600

Subsidiary_Guarantors_Condense

Subsidiary Guarantors (Condensed Consolidating Balance Sheet) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'	'
Accounts receivable - related parties	'	$0
Other current assets	575,431	520,875
Oil and natural gas properties, net	9,167,502	8,831,265
Property and equipment, net	116,159	114,783
Investment in subsidiaries	'	0
Other long-term assets	119,076	124,241
Total assets	9,978,168	9,591,164
LIABILITIES AND EQUITY	'	'
Other current liabilities	938,604	756,868
Other long-term liabilities	1,503,943	1,445,926
Long-term debt	3,674,434	3,630,421
Equity	3,861,187	3,757,949
Total liabilities and stockholders' equity	9,978,168	9,591,164
Parent Company [Member]	'	'
ASSETS	'	'
Accounts receivable - related parties	6,092,946	6,115,554
Other current assets	40,628	39,108
Oil and natural gas properties, net	0	0
Property and equipment, net	0	0
Investment in subsidiaries	4,135,667	3,896,741
Other long-term assets	69,970	74,013
Total assets	10,339,211	10,125,416
LIABILITIES AND EQUITY	'	'
Accounts payable - related parties	1,244,197	1,261,844
Other current liabilities	155,002	126,461
Other long-term liabilities	1,404,391	1,348,741
Long-term debt	3,674,434	3,630,421
Equity	3,861,187	3,757,949
Total liabilities and stockholders' equity	10,339,211	10,125,416
Guarantor Subsidiaries [Member]	'	'
ASSETS	'	'
Accounts receivable - related parties	1,244,197	1,261,844
Other current assets	534,803	481,767
Oil and natural gas properties, net	9,167,502	8,831,265
Property and equipment, net	116,159	114,783
Investment in subsidiaries	0	0
Other long-term assets	49,106	50,228
Total assets	11,111,767	10,739,887
LIABILITIES AND EQUITY	'	'
Accounts payable - related parties	6,092,946	6,115,554
Other current liabilities	783,602	630,407
Other long-term liabilities	99,552	97,185
Long-term debt	0	0
Equity	4,135,667	3,896,741
Total liabilities and stockholders' equity	11,111,767	10,739,887
Consolidation Eliminations [Member]	'	'
ASSETS	'	'
Accounts receivable - related parties	-7,337,143	-7,377,398
Other current assets	0	0
Oil and natural gas properties, net	0	0
Property and equipment, net	0	0
Investment in subsidiaries	-4,135,667	-3,896,741
Other long-term assets	0	0
Total assets	-11,472,810	-11,274,139
LIABILITIES AND EQUITY	'	'
Accounts payable - related parties	-7,337,143	-7,377,398
Other current liabilities	0	0
Other long-term liabilities	0	0
Long-term debt	0	0
Equity	-4,135,667	-3,896,741
Total liabilities and stockholders' equity	($11,472,810)	($11,274,139)

Subsidiary_Guarantors_Condense1

Subsidiary Guarantors (Condensed Consolidating Statement Of Operations) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Condensed Financial Statements Captions [Line Items]	'	'
Total operating revenues	$660,959	$472,127
Total operating costs and expenses	-458,727	-391,376
Income (loss) from continuing operations	202,232	80,751
Interest expense	-56,135	-52,106
Other, net	541	-109
Income before income taxes	146,638	28,536
Income tax expense	-55,331	-10,977
Income from continuing operations	91,307	17,559
Income from discontinued operations, net of tax	'	12,534
Net income	91,307	30,093
Parent Company [Member]	'	'
Condensed Financial Statements Captions [Line Items]	'	'
Total operating revenues	0	0
Total operating costs and expenses	36,153	59,196
Income (loss) from continuing operations	-36,153	-59,196
Interest expense	-56,135	-52,106
Other, net	238,926	160,201
Income before income taxes	146,638	48,899
Income tax expense	-55,331	-10,977
Income from discontinued operations, net of tax	'	-7,829
Net income	91,307	30,093
Guarantor Subsidiaries [Member]	'	'
Condensed Financial Statements Captions [Line Items]	'	'
Total operating revenues	660,959	472,127
Total operating costs and expenses	422,574	332,180
Income (loss) from continuing operations	238,385	139,947
Interest expense	0	0
Other, net	541	-109
Income before income taxes	238,926	139,838
Income tax expense	0	0
Income from discontinued operations, net of tax	'	20,363
Net income	238,926	160,201
Consolidation Eliminations [Member]	'	'
Condensed Financial Statements Captions [Line Items]	'	'
Total operating revenues	0	0
Total operating costs and expenses	0	0
Income (loss) from continuing operations	0	0
Interest expense	0	0
Other, net	-238,926	-160,201
Income before income taxes	-238,926	-160,201
Income tax expense	0	0
Income from discontinued operations, net of tax	'	0
Net income	($238,926)	($160,201)

Subsidiary_Guarantors_Condense2

Subsidiary Guarantors (Condensed Consolidating Statement Of Cash Flows) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Condensed Financial Statements Captions [Line Items]	'	'
Net cash flows provided by (used in) operating activities	$475,980	$219,671
Net cash flows used in investing activities	-574,696	-402,129
Net cash flows provided by (used in) financing activities	98,716	180,552
Net increase (decrease) in cash and cash equivalents	0	-1,906
Cash and cash equivalents at beginning of period	21	2,880
Cash and cash equivalents at end of period	21	974
Parent Company [Member]	'	'
Condensed Financial Statements Captions [Line Items]	'	'
Net cash flows provided by (used in) operating activities	-30,312	-171,843
Net cash flows used in investing activities	-14,837	6,016
Net cash flows provided by (used in) financing activities	45,149	165,827
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Guarantor Subsidiaries [Member]	'	'
Condensed Financial Statements Captions [Line Items]	'	'
Net cash flows provided by (used in) operating activities	506,292	391,514
Net cash flows used in investing activities	-559,859	-408,145
Net cash flows provided by (used in) financing activities	53,567	14,725
Net increase (decrease) in cash and cash equivalents	0	-1,906
Cash and cash equivalents at beginning of period	21	2,880
Cash and cash equivalents at end of period	21	974
Consolidation Eliminations [Member]	'	'
Condensed Financial Statements Captions [Line Items]	'	'
Net cash flows provided by (used in) operating activities	0	0
Net cash flows used in investing activities	0	0
Net cash flows provided by (used in) financing activities	0	0
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	$0	$0

Subsequent_Events_Narrative_De

Subsequent Events (Narrative) (Detail) (USD $)	3 Months Ended	4 Months Ended
	Mar. 31, 2014	9-May-14
		Number
Subsequent Event [Line Items]	'	'
Joint venture initiation date	'	9-May-14
Ownership percentage in joint venture	'	50.00%
Capital expenditure funding in joint venture (percent)	'	50.00%
Capital expenditure funding in joint venture (amount)	'	$95,000,000
Transportation agreement initiation date	'	9-May-14
Transportation agreement term	'	'10 years
Line of credit start date	'	9-May-14
Aggregate maximum borrowing base	3,000,000,000	3,250,000,000
Line Of Credit Facility Amount Outstanding	2,500,000,000	'
Line of credit maturity date	25-Apr-16	9-May-19
Debt instrument basis spread reduction	'	25
Write Off Of Deferred Debt Issuance Cost	'	$4,300,000

Subsequent_Events_New_Commodit

Subsequent Events (New Commodity Derivative Contracts) (Detail) (Subsequent Event [Member])	3 Months Ended								12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2014
	bbl		bbl		bbl		bbl		bbl
Oil Swaps [Member]	'		'		'		'		'
Subsequent Event [Line Items]	'		'		'		'		'
Volume (Bbl/MMBtu) - Current Year	340,000	[1]	455,000	[1]	440,000	[1]	'		1,235,000	[1]
Price per Bbl/MMBtu - Current Year	99.12	[1]	99.53	[1]	99.9	[1]	'		99.55	[1]
Volume (Bbl/MMBtu) - Year One	210,000	[1]	210,000	[1]	360,000	[1]	360,000	[1]	1,140,000	[1]
Price per Bbl/MMBtu - Year One	90.76	[1]	90.76	[1]	91.5	[1]	91.5	[1]	91.23	[1]
Oil Basis Swaps [Member]	'		'		'		'		'
Subsequent Event [Line Items]	'		'		'		'		'
Volume (Bbl/MMBtu) - Current Year	276,000	[2]	0	[2]	0	[2]	'		276,000	[2]
Price per Bbl/MMBtu - Current Year	-3	[2]	0	[2]	0	[2]	'		-3	[2]
Volume (Bbl/MMBtu) - Year One	0	[2]	0	[2]	273,000	[2]	270,000	[2]	543,000	[2]
Price per Bbl/MMBtu - Year One	0	[2]	0	[2]	-3	[2]	-3	[2]	-3	[2]
Natural Gas Basis Swap [Member]	'		'		'		'		'
Subsequent Event [Line Items]	'		'		'		'		'
Volume (Bbl/MMBtu) - Current Year	1,840,000	[3]	1,840,000	[3]	1,220,000	[3]	'		4,900,000	[3]
Price per Bbl/MMBtu - Current Year	-0.11	[3]	-0.11	[3]	-0.11	[3]	'		-0.11	[3]
[1]	(a) The index prices for the oil price swaps are based on the NYMEX b WTI monthly average futures price.
[2]	(b) The basis differential price is between Midland b WTI and Cushing b WTI.
[3]	(c) The basis differential price is between the El Paso Permian delivery point and NYMEX b Henry Hub delivery point.

Supplementary_Information_Capi

Supplementary Information (Capitalized Costs) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Disclosure Supplementary Information Capitalized Costs [Abstract]	'	'
Proved	$10,708,779	$10,182,953
Unproved	1,059,636	1,032,420
Accumulated depletion and depreciation	-2,600,913	-2,384,108
Net capitalized costs for oil and natural gas properties	$9,167,502	$8,831,265

Supplementary_Information_Cost

Supplementary Information (Costs Incurred For Oil And Natural Gas Producing Activities) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Disclosure Supplementary Information Costs Incurred For Oil And Natural Gas Producing Activities [Abstract]	'	'
Proved	$20,490	$1,885
Unproved	24,688	27,896
Exploration	324,497	266,690
Development	211,679	174,722
Total costs incurred for oil and natural gas properties	$581,354	$471,193

Supplementary_Information_Asse

Supplementary Information (Asset Retirement Obligations For Oil and Natural Gas Producing Activities) (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Disclosure Supplementary Information Asset Retirement Obligations For Oil And Natural Gas Producing Activities [Abstract]	'	'
Exploration costs	$558	$734
Development costs	965	1,530
Total	$1,523	$2,264