Rosetta Resources 10-Q 5 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 25, 2014
Document And 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	'ROSE	'
Entity Registrant Name	'ROSETTA RESOURCES INC.	'
Entity Central Index Key	'0001340282	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	61,436,417

Consolidated_Balance_Sheet

Consolidated Balance Sheet (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$55,115	$193,784
Accounts receivable	130,302	122,677
Derivative instruments	37	4,307
Prepaid expenses	7,932	9,860
Deferred income taxes	18,963	27,976
Other current assets	2,164	1,284
Total current assets	214,513	359,888
Oil and natural gas properties using the full cost method of accounting:	'	'
Proved properties	4,387,172	3,951,397
Unproved/unevaluated properties, not subject to amortization	727,051	755,438
Gathering systems and compressor stations	204,944	168,730
Other fixed assets	27,299	26,362
Total property and equipment, gross	5,346,466	4,901,927
Accumulated depreciation, depletion and amortization, including impairment	-2,094,737	-2,020,879
Total property and equipment, net	3,251,729	2,881,048
Other assets:	'	'
Debt issuance costs	24,590	25,602
Derivative instruments	2,710	5,458
Other long-term assets	327	4,622
Total other assets	27,627	35,682
Total assets	3,493,869	3,276,618
Current liabilities:	'	'
Accounts payable and accrued liabilities	286,397	190,950
Royalties and other payables	83,542	78,264
Derivative instruments	13,738	4,913
Total current liabilities	383,677	274,127
Long-term liabilities:	'	'
Derivative instruments	438	433
Long-term debt	1,560,000	1,500,000
Deferred income taxes	145,998	136,407
Other long-term liabilities	18,744	17,317
Total liabilities	2,108,857	1,928,284
Commitments and Contingencies (Note 9)	'	'
Stockholders' equity:	'	'
Preferred stock, $0.001 par value; authorized 5,000,000 shares; no shares issued in 2014 or 2013	'	'
Common stock, $0.001 par value; authorized 150,000,000 shares; issued 62,200,386 shares and 62,032,162 shares at March 31, 2014 and December 31, 2013, respectively	62	61
Additional paid-in capital	1,186,236	1,182,672
Treasury stock, at cost; 773,061 shares and 724,755 shares at March 31, 2014 and December 31, 2013, respectively	-26,725	-24,592
Accumulated other comprehensive loss	-105	-108
Retained earnings	225,544	190,301
Total stockholders' equity	1,385,012	1,348,334
Total liabilities and stockholders' equity	$3,493,869	$3,276,618

Consolidated_Balance_Sheet_Par

Consolidated Balance Sheet (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Statement Of Financial Position [Abstract]	'	'
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	62,200,386	62,032,162
Treasury stock, shares	773,061	724,755

Consolidated_Statement_of_Oper

Consolidated Statement of Operations (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenues:	'	'
Oil sales	$131,677	$110,052
NGL sales	55,295	46,461
Natural gas sales	51,379	33,576
Derivative instruments	-23,785	-11,969
Total revenues	214,566	178,120
Operating costs and expenses:	'	'
Lease operating expense	19,521	8,911
Treating and transportation	20,677	15,087
Taxes, other than income	10,206	7,655
Depreciation, depletion and amortization	74,775	44,630
General and administrative costs	19,538	15,532
Total operating costs and expenses	144,717	91,815
Operating income	69,849	86,305
Other expense (income):	'	'
Interest expense, net of interest capitalized	15,290	6,069
Interest income	-12	'
Other expense (income), net	151	-30
Total other expense	15,429	6,039
Income before provision for income taxes	54,420	80,266
Income tax expense	19,177	26,786
Net income	$35,243	$53,480
Earnings per share:	'	'
Basic	$0.57	$1.01
Diluted	$0.57	$1.01
Weighted average shares outstanding:	'	'
Basic	61,380	52,733
Diluted	61,547	53,081

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]	'	'
Net income	$35,243	$53,480
Other comprehensive income:	'	'
Amortization of accumulated other comprehensive gain (loss) related to de-designated hedges, net of income taxes of ($154) for the three months ended March 31, 2013	'	271
Postretirement medical benefits prior service benefit (cost), net of income taxes of ($2) and $104, respectively	3	-185
Other comprehensive income	3	86
Comprehensive income	$35,246	$53,566

Consolidated_Statement_of_Comp1

Consolidated Statement of Comprehensive Income (Unaudited) (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]	'	'
Amortization of accumulated other comprehensive gain (loss) related to de-designated hedges, income taxes	'	($154)
Postretirement medical benefits prior service cost, income tax benefit	($2)	$104

Consolidated_Statement_of_Cash

Consolidated Statement of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:	'	'
Net income	$35,243	$53,480
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation, depletion and amortization	74,775	44,630
Deferred income taxes	18,604	26,060
Amortization of deferred loan fees recorded as interest expense	984	538
Stock-based compensation expense	3,358	2,664
Loss (gain) due to change in fair value of derivative instruments	15,848	13,971
Change in operating assets and liabilities:	'	'
Accounts receivable	-7,625	-2,955
Prepaid expenses	1,956	771
Other current assets	-880	'
Long-term assets	43	-1
Accounts payable and accrued liabilities	3,264	-729
Royalties and other payables	5,277	4,476
Other long-term liabilities	377	-1,266
Net cash provided by operating activities	151,224	141,639
Cash flows from investing activities:	'	'
Deposit on Permian acquisition	'	-38,400
Acquisitions of oil and gas assets	-79,015	'
Additions to oil and gas assets	-268,836	-175,849
Disposals of oil and gas assets	8	-2,651
Net cash used in investing activities	-347,843	-216,900
Cash flows from financing activities:	'	'
Borrowings on Credit Facility	80,000	140,000
Payments on Credit Facility	-20,000	-85,000
Proceeds from stock options exercised	61	408
Purchases of treasury stock	-2,133	-6,256
Excess tax benefit from share-based awards	22	'
Net cash provided by financing activities	57,950	49,152
Net decrease in cash	-138,669	-26,109
Cash and cash equivalents, beginning of period	193,784	36,786
Cash and cash equivalents, end of period	55,115	10,677
Supplemental disclosures:	'	'
Capital expenditures included in Accounts payable and accrued liabilities	$206,867	$77,867

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (Unaudited) (USD $)	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive (Loss)/Income [Member]	Retained Earnings [Member]
In Thousands, except Share data
Balance at December 31, 2013 at Dec. 31, 2013	$1,348,334	$61	$1,182,672	($24,592)	($108)	$190,301
Balance, Treasury Stock, Shares at Dec. 31, 2013	724,755	'	'	724,755	'	'
Balance, Common Stock Shares at Dec. 31, 2013	'	62,032,162	'	'	'	'
Excess tax benefit from share-based awards	22	'	22	'	'	'
Stock options exercised	62	1	61	'	'	'
Stock options exercised, shares	'	2,500	'	'	'	'
Treasury stock-employee tax payment	-2,133	'	'	-2,133	'	'
Treasury Stock, Shares, Acquired	'	'	'	48,306	'	'
Stock-based compensation	3,481	'	3,481	'	'	'
Vesting of restricted stock	'	'	'	'	'	'
Vesting of restricted stock, Shares	'	165,724	'	'	'	'
Comprehensive income	35,246	'	'	'	3	35,243
Balance at March 31, 2014 at Mar. 31, 2014	$1,385,012	$62	$1,186,236	($26,725)	($105)	$225,544
Balance, Treasury Stock, Shares at Mar. 31, 2014	773,061	'	'	773,061	'	'
Balance, Common Stock, Shares at Mar. 31, 2014	'	62,200,386	'	'	'	'

Organization_and_Operations_of

Organization and Operations of the Company	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Organization and Operations of the Company	'
	(1) Organization and Operations of the Company
	Nature of Operations. Rosetta Resources Inc. (together with its consolidated subsidiaries, the “Company”) is an independent exploration and production company engaged in the acquisition and development of onshore energy resources in the United States of America. The Company’s operations are located in the Eagle Ford shale in South Texas and the Permian Basin in West Texas.
	These interim financial statements have not been audited. However, in the opinion of management, all adjustments, consisting of normal recurring adjustments necessary to fairly state the financial statements, have been included. Results of operations for interim periods are not necessarily indicative of the results of operations that may be expected for the entire year. In addition, these financial statements have been prepared in accordance with the instructions to Form 10-Q and, therefore, do not include all disclosures required for financial statements prepared in conformity with accounting principles generally accepted in the U.S. (“GAAP”). These financial statements and notes should be read in conjunction with the Company’s audited Consolidated Financial Statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 (“2013 Annual Report”).

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	(2) Summary of Significant Accounting Policies
	The Company has provided a discussion of significant accounting policies, estimates and judgments in its 2013 Annual Report. There have been no changes to the Company’s significant accounting policies since December 31, 2013.
	Recent Accounting Developments
	There have been no recently issued accounting developments that have been applied or may impact the Company in future periods.

Property_and_Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2014
Extractive Industries [Abstract]	'
Property and Equipment	'
	(3) Property and Equipment
	The Company’s Total property and equipment, net consists of the following:
			March 31, 2014			December 31, 2013
			(In thousands)
	Proved properties		$	4,387,172		$	3,951,397
	Unproved/unevaluated properties			727,051			755,438
	Gathering systems and compressor stations			204,944			168,730
	Other fixed assets			27,299			26,362
	Total			5,346,466			4,901,927
	Less: Accumulated depreciation, depletion and amortization			(2,094,737	)		(2,020,879	)
	Total property and equipment, net		$	3,251,729		$	2,881,048
	Acquisitions
	2014 Permian Acquisition. On December 30, 2013, the Company entered into a definitive agreement with several private parties to acquire Delaware Basin assets covering 5,034 net acres located in Reeves County (the “2014 Permian Acquisition”). These assets include 13 gross producing wells, of which 11 are operated by the Company. The Company completed the 2014 Permian Acquisition on February 28, 2014, with an effective date of December 1, 2013, for total cash consideration of $83.2 million, subject to further customary post-closing adjustments.
	Gates Ranch Acquisition. In the second quarter of 2013, the Company acquired the remaining 10% working interest in certain producing wells along with a third party’s option to participate in future wells in certain leases of its Gates Ranch leasehold located in the Eagle Ford shale (the “Gates Acquisition”) in Webb County for total cash consideration of approximately $128.1 million. The transaction closed on June 5, 2013 (the “Gates Acquisition Date”) and was financed with borrowings under the Company’s senior secured revolving credit facility (the “Credit Facility”), as described in Note 7 – Debt and Credit Agreements. As of the Gates Acquisition Date, the Company owns a 100% working interest in the entire Gates Ranch leasehold.
	2013 Permian Acquisition. On March 14, 2013, the Company entered into a purchase and sale agreement with Comstock Oil & Gas, LP to purchase producing and undeveloped oil and natural gas interests in the Permian Basin in Gaines and Reeves Counties, Texas (the “2013 Permian Acquisition”). The Company completed the 2013 Permian Acquisition on May 14, 2013, with an effective date of January 1, 2013, for total cash consideration of $825.2 million. The 2013 Permian Acquisition was financed with the proceeds from the Company’s issuance of the 5.625% Senior Notes, as described in Note 7 – Debt and Credit Agreements, and the common stock offering described in Note 10 – Equity. In connection with the 2013 Permian Acquisition and related financings, the Company incurred total transaction costs of approximately $31.0 million, including (i) $5.6 million of commitment fees and related expenses associated with a bridge credit facility (“Bridge Credit Facility”), which were recorded as Interest expense since the Company did not borrow under the Bridge Credit Facility, (ii) $10.0 million of debt issuance costs paid in connection with the issuance of the 5.625% Senior Notes, which were deferred and are being amortized over the term of these senior notes, (iii) $13.1 million of equity issuance costs and related expenses associated with the common stock offering, which were reflected as a reduction of equity proceeds, and (iv) $2.3 million of consulting, investment, advisory, legal and other acquisition-related fees, which were expensed and are included in General and administrative costs.
	The above transactions were accounted for under the acquisition method of accounting, whereby each respective purchase price was allocated to the assets acquired and liabilities assumed based on their estimated fair values, with any excess of the purchase price over the estimated fair value of the identifiable net assets acquired recorded as goodwill (or shortfall of purchase price versus net fair value recorded as bargain purchase). Based on the final purchase price allocations for the Gates Acquisition and the 2013 Permian Acquisition and the preliminary purchase price allocation for the 2014 Permian Acquisition, no goodwill or bargain purchase was recognized. The final purchase price allocation for the 2013 Permian and Gates Ranch Acquisitions and the preliminary purchase price allocation for the 2014 Permian Acquisition, representing consideration paid, assets acquired and liabilities assumed as of the respective acquisition dates, are shown in the tables below.
	2013 Permian Acquisition and Gates Ranch Acquisition
			Final Total Purchase Price
			Allocation
			(in thousands)
	Cash consideration		$	953,242
	Fair value of assets acquired:
	Other fixed assets		$	600
	Oil and natural gas properties
	Proved properties			290,273
	Unproved/unevaluated properties			663,300
	Total assets acquired		$	954,173
	Fair value of liabilities assumed:
	Asset retirement obligations		$	931
	Net assets acquired		$	953,242
	2014 Permian Acquisition
			Preliminary Total Purchase Price
			Allocation
			(in thousands)
	Cash consideration		$	83,172
	Fair value of assets acquired:
	Oil and natural gas properties
	Proved properties		$	61,598
	Unproved/unevaluated properties			21,867
	Total assets acquired		$	83,465
	Fair value of liabilities assumed:
	Asset retirement obligations		$	293
	Net assets acquired		$	83,172
	The fair value measurements of assets acquired and liabilities assumed are based on inputs that are not observable in the market and therefore represent Level 3 inputs. The fair values of oil and natural gas properties and asset retirement obligations were measured using valuation techniques that convert future cash flows to a single discounted amount. Significant inputs to the valuation of oil and natural gas properties included estimates of: (i) reserves, including risk adjustments for probable and possible reserves; (ii) production rates; (iii) future operating and development costs; (iv) future commodity prices; (v) future cash flows; and (vi) a market-based weighted average cost of capital rate. These inputs required significant judgments and estimates by the Company’s management at the time of the valuation and are the most sensitive and subject to change. See Note 5 – Fair Value Measurements for additional information.
	The results of operations attributable to the 2014 Permian Acquisition were included in the Company’s Consolidated Statement of Operations beginning on March 1, 2014 and increased Total revenues and Operating income by $1.6 million and $1.1 million, respectively.
	The following unaudited pro forma information assumes the transactions and related financings for the 2013 Permian Acquisition and the Gates Acquisition occurred on January 1, 2012 and the transaction for the 2014 Permian Acquisition occurred on January 1, 2013. The unaudited pro forma information includes the effects of issuing the 5.625% Senior Notes, the issuance of common stock in the equity offering and the use of proceeds from the debt and equity offerings as discussed above. The pro forma results of operations have been prepared by adjusting the Company’s historical results to include the historical results of the acquired assets based on information provided by the seller, the Company’s knowledge of the acquired properties and the impact of the Company’s purchase price allocation. The Company believes the assumptions used provide a reasonable basis for reflecting the pro forma significant effects directly attributable to the acquisitions and associated financings. The pro forma results of operations do not include any cost savings or other synergies that may result from the 2014 Permian Acquisition and the 2013 Permian Acquisition or any estimated costs that have been or will be incurred by the Company to integrate the Delaware or Permian assets. The pro forma information does not purport to represent what the Company’s results of operations would have been if the 2013 Permian Acquisition and Gates Acquisition had occurred on January 1, 2012 and the 2014 Permian Acquisition had occurred on January 1, 2013.
			Three Months Ended March 31,
			2014 (1)			2013
			(In thousands, except per share and share data)
	Total revenues		$	218,306		$	202,914
	Net income			36,147			51,860
	Earnings per share:
	Basic		$	0.59		$	0.85
	Diluted		$	0.59		$	0.85
	Weighted average shares outstanding:
	Basic			61,380			60,783
	Diluted			61,547			61,131
	-1	No pro forma adjustments were made related to the 2013 Permian Acquisition and Gates Acquisition for the period as the acquisitions and related financings are included in the Company’s historical results.
	Additional Disclosures about Property and Equipment
	The Company capitalizes internal costs directly identified with acquisition, exploration and development activities. The Company capitalized $1.6 million and $2.1 million of internal costs for the three months ended March 31, 2014 and 2013, respectively.
	Oil and gas properties include unevaluated property costs of $727.1 million and $755.4 million as of March 31, 2014 and December 31, 2013, respectively, which are not being amortized. These amounts primarily represent acquisition costs of unproved properties and unevaluated exploration projects in which the Company owns a direct interest. Such costs are periodically evaluated for impairment, and upon evaluation or impairment are transferred to the Company’s full cost pool and amortized.
	Pursuant to full cost accounting rules, the Company must perform a ceiling test each quarter on its proved oil and natural gas assets within each separate cost center. All of the Company’s costs are included in one cost center because all of the Company’s operations are located in the United States. The Company’s ceiling test was calculated using trailing twelve-month, unweighted-average first-day-of-the-month prices for oil and natural gas as of March 31, 2014, which were based on a West Texas Intermediate oil price of $94.92 per Bbl and a Henry Hub natural gas price of $3.99 per MMBtu (adjusted for basis and quality differentials), respectively. Utilizing these prices, the calculated ceiling amount exceeded the net capitalized cost of oil and natural gas properties as of March 31, 2014, and as a result, no write-down was recorded. It is possible that a write-down of the Company’s oil and gas properties could occur in future periods in the event that oil and natural gas prices significantly decline or the Company experiences significant downward adjustments to its estimated proved reserves.

Commodity_Derivative_Contracts

Commodity Derivative Contracts	3 Months Ended
	Mar. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Commodity Derivative Contracts	'
	(4) Commodity Derivative Contracts
	The Company is exposed to various market risks, including volatility in oil, natural gas liquids (“NGL”) and natural gas prices, which are managed through derivative instruments. The level of derivative activity utilized depends on market conditions, operating strategies and available derivative prices. The Company utilizes various types of derivative instruments to manage commodity price risk, including fixed price swaps and costless collars. Forward contracts on various commodities are entered into to manage the price risk associated with forecasted sales of the Company’s oil, NGL and natural gas production.
	As of March 31, 2014, the following derivative contracts were outstanding with associated notional volumes and average underlying prices that represent hedged prices of commodities at various market locations:
	Product	Settlement				Derivative	Notional			Total		Average		Average
		Period				Instrument	Daily			Notional		Floor/Fixed Prices		Ceiling Prices
							Volume			Volume		per Bbl		per Bbl
							(Bbls)			(Bbls)
	Crude oil		2014			Costless Collar		3,000			825,000	$	83.33	$	109.63
	Crude oil		2014			Swap		6,000			1,650,000		93.13
	Crude oil		2015			Swap		10,000			3,650,000		88.58
	Crude oil		2016			Swap		1,000			366,000		84.4
											6,491,000
	Product	Settlement				Derivative	Notional			Total		Average
		Period				Instrument	Daily			Notional		Fixed Prices
							Volume			Volume		per Bbl
							(Bbls)			(Bbls)
	NGL-Ethane		2014			Swap		4,500			1,237,500	$	13.21
	NGL-Propane		2014			Swap		2,785			765,875		44.71
	NGL-Isobutane		2014			Swap		930			255,750		61.26
	NGL-Normal Butane		2014			Swap		875			240,625		60.29
	NGL-Pentanes Plus		2014			Swap		910			250,250		84.97
	NGL-Ethane		2015			Swap		2,500			912,500		11.59
	NGL-Propane		2015			Swap		1,250			456,250		43.26
	NGL-Isobutane		2015			Swap		450			164,250		53.76
	NGL-Normal Butane		2015			Swap		400			146,000		53.76
	NGL-Pentanes Plus		2015			Swap		400			146,000		76.44
											4,575,000
	Product	Settlement				Derivative	Notional			Total		Average		Average
		Period				Instrument	Daily			Notional		Floor/Fixed Prices		Ceiling Prices
							Volume			Volume		per MMBtu		per MMBtu
							(MMBtu)			(MMBtu)
	Natural gas		2014			Costless Collar		50,000			13,750,000		3.6		4.94
	Natural gas		2015			Costless Collar		50,000			18,250,000		3.6		5.04
	Natural gas		2014			Swap		30,000			8,250,000		4.07
	Natural gas		2015			Swap		40,000			14,600,000		4.18
	Natural gas		2016			Swap		20,000			7,320,000		4.02
											62,170,000
	As of March 31, 2014, the Company’s derivative instruments were with counterparties who are lenders under its Credit Facility. This practice allows the Company to satisfy any need for margin obligations resulting from an adverse change in the fair market value of its derivative contracts with the collateral securing its Credit Facility, thus eliminating the need for independent collateral postings. The Company’s ability to continue satisfying any applicable margin requirements in this manner may be subject to change as described in Items 1 and 2. Business and Properties – Government Regulation in the Company’s 2013 Annual Report. As of March 31, 2014, the Company had no deposits for collateral regarding commodity derivative positions.
	Discontinuance of Hedge Accounting
	Effective January 1, 2012, the Company elected to de-designate all commodity contracts previously designated as cash flow hedges as of December 31, 2011 and discontinue hedge accounting prospectively. As of December 31, 2013, all frozen mark-to-market values included in Accumulated other comprehensive income were reclassified into earnings. With the election to de-designate hedging instruments, all of the Company’s derivative instruments continue to be recorded at fair value with unrealized gains and losses recognized immediately in earnings rather than in Accumulated other comprehensive income. These mark-to-market adjustments produce a degree of earnings volatility that can be significant from period to period, but such adjustments had no cash flow impact in the current period. The cash flow impact occurs upon settlement of the underlying contract.
	Additional Disclosures about Derivative Instruments
	Authoritative derivative guidance requires companies to recognize all derivative instruments as either assets or liabilities at fair value in the Company’s financial statements. The following table sets forth information on the location and amounts of the Company’s derivative instrument fair values in the Consolidated Balance Sheet as of March 31, 2014 and December 31, 2013, respectively:
				Asset (Liability) Fair Value
				March 31, 2014			December 31, 2013
	Commodity derivative contracts	Location on Consolidated Balance Sheet		(In thousands)
	Oil	Derivative instruments—current assets		$	—		$	1,299
	Oil	Derivative instruments—non-current assets			1,055			2,117
	Oil	Derivative instruments—current liabilities			(10,837	)		(5,629	)
	Oil	Derivative instruments—non-current liabilities			(2,159	)		—
	NGL	Derivative instruments—current assets			37			2,834
	NGL	Derivative instruments—non-current assets			274			(129	)
	NGL	Derivative instruments—current liabilities			2,909			461
	NGL	Derivative instruments—non-current liabilities			299			(433	)
	Natural gas	Derivative instruments—current assets			—			174
	Natural gas	Derivative instruments—non-current assets			1,381			3,470
	Natural gas	Derivative instruments—current liabilities			(5,810	)		255
	Natural gas	Derivative instruments—non-current liabilities			1,422			—
	Total derivative fair value, net, not designated as hedging instruments			$	(11,429	)	$	4,419
	The following table sets forth information on the location and amounts of derivative gains and losses in the Consolidated Statement of Operations for the three months ended March 31, 2014 and 2013, respectively:
				Three Months Ended March 31,
	Location on Consolidated			2014			2013
	Statement of Operations	Description of (Loss) Gain		(In thousands)
	Derivative instruments	(Loss) gain recognized in income			(7,937	)		2,002
	Realized (loss) gain recognized in income		$	(7,937	)	$	2,002
Derivative instruments	Loss recognized in income due to changes in fair value		$	(15,848	)	$	(13,546	)
Derivative instruments	Loss reclassified from Accumulated OCI			—			(425	)
	Unrealized loss recognized in income		$	(15,848	)	$	(13,971	)
	Total commodity derivative loss recognized in income		$	(23,785	)	$	(11,969	)

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	(5) Fair Value Measurements
	The Company’s financial assets and liabilities are measured at fair value on a recurring basis. The Company measures its non-financial assets and liabilities, such as asset retirement obligations and other property and equipment, at fair value on a non-recurring basis. See Note 3 – Property and Equipment for more information on the Company’s fair value measurement of non-recurring assets and liabilities related to the 2014 Permian Acquisition.
	As defined in the guidance of the Financial Accounting Standards Board (“FASB”), fair value is the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). To estimate fair value, the Company utilizes market data and assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated or generally unobservable.
	The FASB’s guidance establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted market prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). The three levels of the fair value hierarchy are as follows:
		•		“Level 1” inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities.
		•		“Level 2” inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument.
		•		“Level 3” inputs are 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.
	As required, financial assets and liabilities are classified in their entirety 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 fair value assets and liabilities along with their placement within the fair value hierarchy levels. The Company determines the appropriate level for each financial asset and liability on a quarterly basis and recognizes any transfers at the end of the reporting period.
	The following table sets forth by level within the fair value hierarchy the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis for the respective period:
			Fair value as of March 31, 2014
			Level 1			Level 2			Level 3			Netting (1)			Total
			(In thousands)
	Assets:
	Money market funds		$	—		$	1,035		$	—		$	—		$	1,035
	Commodity derivative contracts			—			—			13,992			(11,245	)		2,747
	Liabilities:
	Commodity derivative contracts			—			—			(25,421	)		11,245			(14,176	)
	Total fair value		$	—		$	1,035		$	(11,429	)	$	—		$	(10,394	)
			Fair value as of December 31, 2013
			Level 1			Level 2			Level 3			Netting (1)			Total
			(In thousands)
	Assets:
	Money market funds		$	—		$	1,035		$	—		$	—		$	1,035
	Commodity derivative contracts			—			—			21,675			(11,910	)		9,765
	Liabilities:
	Commodity derivative contracts			—			—			(17,256	)		11,910			(5,346	)
	Total fair value		$	—		$	1,035		$	4,419		$	—		$	5,454
	-1	Represents the impact of netting commodity derivative assets and liabilities with counterparties where the Company has the contractual right and intends to net settle. No margin or collateral balances are deposited with counterparties and as such, gross amounts are offset to determine the net amounts presented in the Consolidated Balance Sheet.
	The Company’s Level 3 instruments include commodity derivative contracts for which fair value is determined by a third-party provider. Although the Company compares the fair values derived from the third-party provider with its counterparties, the Company does not currently have sufficient corroborating market evidence to support classifying these contracts as Level 2 instruments and does not have access to the specific valuation models or certain inputs used by its third-party provider or counterparties. Therefore, these commodity derivative contracts are classified as Level 3 instruments.
	The following table presents a range of the unobservable inputs provided by the Company’s third-party provider utilized in the fair value measurements of the Company’s assets and liabilities classified as Level 3 instruments as of March 31, 2014 (in thousands):
			Asset						Range						Weighted
	Level 3 Instrument		(Liability)			Valuation Technique		Unobservable Input	Minimum			Maximum			Average
	Oil swaps		$	(12,050	)	Discounted cash flow		Forward price curve-swaps	$	82.94		$	101.36		$	91.81
	Oil costless collars			110		Option model		Forward price curve- costless collar option value		(1.45	)		2.28			0.13
	NGL swaps			5,263		Discounted cash flow		Forward price curve-swaps		0.27			1.31			0.55
	NGL swaps			(1,744	)	Discounted cash flow		Forward price curve-swaps		1			2.17			1.3
	Natural gas swaps			(3,017	)	Discounted cash flow		Forward price curve-swaps		3.95			4.52			4.24
	Natural gas swaps			703		Discounted cash flow		Forward price curve-swaps		3.87			4.68			4.13
	Natural gas costless collars			(1,031	)	Option model		Forward price curve- costless collar option value		(0.28	)		0.12			(0.07	)
	Natural gas costless collars			337		Option model		Forward price curve- costless collar option value		(0.37	)		0.29			0.02
	Total		$	(11,429	)
	The determination of derivative fair values by the third-party provider incorporates a credit adjustment for nonperformance risk, including the credit standing of the counterparties involved, and the impact of the Company’s nonperformance risk on its liabilities. The Company recorded an upward adjustment to the fair value of its derivative instruments in the amount of $0.2 million as of March 31, 2014.
	The significant unobservable inputs for Level 3 derivative contracts include forward price curves and option values. Significant increases (decreases) in the quoted forward prices for commodities and option values generally lead to corresponding decreases (increases) in the fair value measurement of the Company’s oil, NGL and natural gas derivative contracts.
	The tables below present reconciliations of financial assets and liabilities classified as Level 3 in the fair value hierarchy during the indicated periods.
			Derivative
			Asset (Liability)
			(In thousands)
	Balance at January 1, 2014		$	4,419
	Total Gains or (Losses) (Realized or Unrealized):
	Included in Earnings			(23,785	)
	Purchases, Issuances and Settlements:
	Settlements			7,937
	Transfers in and out of Level 3			—
	Balance at March 31, 2014		$	(11,429	)
			Derivative
			Asset (Liability)
			(In thousands)
	Balance at January 1, 2013		$	20,664
	Total Gains or (Losses) (Realized or Unrealized):
	Included in Earnings			(11,544	)
	Purchases, Issuances and Settlements:
	Settlements			(2,002	)
	Transfers in and out of Level 3			—
Balance at March 31, 2013		$	7,118
Fair Value of Other Financial Instruments
All of the Company’s other financial instruments (excluding derivatives) are presented on the balance sheet at carrying value. As of March 31, 2014, the carrying value of cash and cash equivalents (excluding money market funds), other current assets and current liabilities reported in the Consolidated Balance Sheet approximate fair value because of their short-term nature, and all such financial instruments are considered Level 1 instruments.
The Company’s debt consists of publicly traded Senior Notes (defined below) and borrowings under the Credit Facility. The fair values of the Company’s Senior Notes are based upon unadjusted quoted market prices and are considered Level 1 instruments. The Company’s borrowings under the Credit Facility approximate fair value as the interest rates are variable and reflective of current market rates, and are therefore considered a Level 1 instrument. As of March 31, 2014, the carrying amount of total debt was $1.560 billion and the estimated fair value of total debt was $1.606 billion.

Asset_Retirement_Obligations

Asset Retirement Obligations	3 Months Ended
	Mar. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]	'
Asset Retirement Obligations	'
	(6) Asset Retirement Obligations
	The following table provides a rollforward of the Company’s asset retirement obligations (“ARO”). Liabilities incurred during the period include additions to obligations and obligations incurred from acquisitions. Liabilities settled during the period include settlement payments for obligations. Activity related to the Company’s ARO is as follows:
		Three Months Ended
		March 31, 2014
		(In thousands)
	ARO as of December 31, 2013	$	13,057
	Liabilities incurred during period		810
	Liabilities settled during period		—
	Accretion expense		232
	ARO as of March 31, 2014	$	14,099
	As of March 31, 2014, the $4.0 million current portion of the total ARO is included in Accrued liabilities, and the $10.1 million long-term portion of ARO is included in Other long-term liabilities on the Consolidated Balance Sheet.

Debt_and_Credit_Agreements

Debt and Credit Agreements	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Debt and Credit Agreements	'
	(7) Debt and Credit Agreements
	Senior Secured Revolving Credit Facility. As of March 31, 2014, the Company had $60.0 million outstanding with $740.0 million of available borrowing capacity under its Credit Facility. Amounts outstanding under the Credit Facility bear interest at specified margins over the London Interbank Offered Rate (LIBOR) of 1.50% to 2.50% and mature in April 2018. Additionally, the Company can borrow under the Credit Facility at the Alternative Base Rate (ABR), which is based upon the Prime Rate in effect on such day plus a margin of 0.5% to 1.5% depending on the Company’s utilization percentage. The weighted average borrowing rate for the three months ended March 31, 2014 under the Credit Facility was 4.38%, inclusive of interest and commitment fees. For the three months ended March 31, 2014, total interest expense and commitment fees under the Credit Facility were $0.8 million. Borrowings under the Credit Facility are collateralized by liens and security interests on substantially all of the Company’s assets, including a mortgage lien on oil and natural gas properties having at least 80% of the pre-tax SEC PV-10 proved reserve value, a guaranty by all of the Company’s domestic subsidiaries and a pledge of 100% of the membership and limited partnership interests of the Company’s domestic subsidiaries. Collateralized amounts under the mortgages are subject to semi-annual reviews based on updated reserve information. The Company is also subject to certain financial covenants, including the requirement to maintain a minimum current ratio of consolidated current assets, including the unused amount of available borrowing capacity, to consolidated current liabilities, excluding certain non-cash obligations, of not less than 1.0 to 1.0 as of the end of each fiscal quarter. The terms of the credit agreement also require the maintenance of a maximum leverage ratio of total debt to earnings before interest expense, income taxes and noncash items, such as depreciation, depletion, amortization and impairment, of not greater than 4.0 to 1.0, calculated at the end of each fiscal quarter for the four fiscal quarters then ended, measured quarterly after giving pro forma effect to acquisitions and divestitures. As of March 31, 2014, the Company’s current ratio was 2.6 and leverage ratio was 2.6. In addition, the Company is subject to covenants limiting dividends and other restricted payments, transactions with affiliates, incurrence of debt, changes of control, asset sales and liens on properties.
	9.500% Senior Notes. On April 15, 2010, the Company issued and sold $200.0 million in aggregate principal amount of 9.500% Senior Notes due 2018 (the “9.500% Senior Notes”) in a private offering. Interest is payable on the 9.500% Senior Notes semi-annually on April 15 and October 15. The 9.500% Senior Notes were issued under an indenture (the “9.500% Senior Notes Indenture”) with Wells Fargo Bank, National Association, as trustee. Under the indenture, the Company has the option to redeem the notes on or after April 15, 2014 at a price of 104.75% of the principal amount, plus accrued and unpaid interest. Provisions of the 9.500% Senior Notes Indenture limit the Company’s ability to, among other things, incur additional indebtedness; pay dividends on capital stock or purchase, repurchase, redeem, defease or retire capital stock or subordinated indebtedness; make investments; incur liens; create any consensual restriction on the ability of the Company’s restricted subsidiaries to pay dividends, make loans or transfer property to the Company; engage in transactions with affiliates; sell assets; and consolidate, merge or transfer assets. The 9.500% Senior Notes Indenture also contains customary events of default. On September 21, 2010, the Company exchanged all of the privately placed 9.500% Senior Notes for registered 9.500% Senior Notes which contain terms substantially identical to the terms of the privately placed notes.
	5.625% Senior Notes. On May 2, 2013, the Company completed its public offering of $700.0 million in aggregate principal amount of 5.625% Senior Notes due 2021 (the “5.625% Senior Notes”). Interest is payable on the 5.625% Senior Notes semi-annually on May 1 and November 1. The 5.625% Senior Notes were issued under an indenture (the “Base Indenture”), as supplemented by a first supplemental indenture with Wells Fargo Bank, National Association, as trustee, which contains covenants and events of default substantially similar to those in the 9.500% Senior Notes Indenture.
	5.875% Senior Notes. On November 15, 2013, the Company completed its public offering of $600.0 million in aggregate principal amount of 5.875% Senior Notes due 2022 (the “5.875% Senior Notes” and, together with the 9.500% Senior Notes and the 5.625% Senior Notes, the “Senior Notes”). Interest is payable on the 5.875% Senior Notes semi-annually on June 1 and December 1. The 5.875% Senior Notes were issued under the Base Indenture, as supplemented by a second supplemental indenture with Wells Fargo Bank, National Association, as trustee, which contains covenants and events of default substantially similar to those in the 9.500% Senior Notes Indenture.
	Total Indebtedness. As of March 31, 2014, the Company had total outstanding borrowings of $1.560 billion, and for the three months ended March 31, 2014, the Company’s weighted average borrowing rate was 6.26%, inclusive of interest and commitment fees.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	(8) Income Taxes
	The Company’s effective tax rate for the three months ended March 31, 2014 and 2013 was 35.2% and 33.4%, respectively. The provision for income taxes for the three months ended March 31, 2014 differs from the tax computed at the federal statutory income tax rate primarily due to the impact of state income taxes and the deductibility of certain incentive compensation. As of March 31, 2014 and December 31, 2013, the Company had no unrecognized tax benefits. The Company does not anticipate that total unrecognized tax benefits will significantly change due to the settlement of audits or the expiration of statutes of limitation within the next twelve months.
	The Company provides for deferred income taxes on the difference between the tax basis of an asset or liability and its carrying amount in the financial statements in accordance with authoritative guidance for accounting for income taxes. This difference will result in taxable income or deductions in future years when the reported amount of the asset or liability is recovered or settled, respectively. Considerable judgment is required in determining when these events may occur and whether recovery of an asset is more likely than not. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. As of March 31, 2014, the Company had a net deferred tax liability of $127.0 million resulting primarily from the differences between the book basis and tax basis of the Company’s oil and natural gas properties, partially offset by net operating loss carryforwards.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	(9) Commitments and Contingencies
	Firm Oil and Natural Gas Transportation and Processing Commitments. The Company has commitments for the transportation and processing of its production in the Eagle Ford area and has an aggregate minimum commitment to deliver 4.5 MMBbls of oil by the end of 2017 and 321 million MMBtus of natural gas by the end of 2023. The Company is required to make periodic deficiency payments for any shortfalls in delivering the minimum volumes under these commitments. Currently, the Company has insufficient production to meet all of these contractual commitments. As the Company develops additional reserves in the Eagle Ford area, it anticipates exceeding its current minimum volume commitments and therefore intends to enter into additional transportation and processing commitments in the future. These future transportation and processing commitments could expose the Company to additional volume deficiency payments. As of March 31, 2014, the Company has accrued deficiency fees of $2.4 million and expects to continue to accrue deficiency fees under its commitments. Future obligations under firm oil and natural gas transportation and processing agreements as of March 31, 2014 are as follows:
		March 31, 2014
		(In thousands)
	2015	$	34,313
	2016		33,844
	2017		33,388
	2018		29,839
	2019		27,580
	Thereafter		76,508
	Total future obligations	$	235,472
	Drilling Rig and Completion Services Commitments. Drilling rig and completion services commitments represent obligations with certain contractors to execute the Company’s Eagle Ford and Permian Basin drilling programs. As of March 31, 2014, the Company had three outstanding drilling rig commitments with terms greater than one year that will expire by the end of 2016, and minimum contractual commitments due in the next twelve months were $23.3 million. Payments under these commitments are accounted for as capital additions to oil and gas properties. As of March 31, 2014, the Company’s minimum contractual commitments due in the next twelve months for completion services agreements for the stimulation, cementing and delivery of drilling fluids and other field service commitments were $7.8 million. Payments under these commitments are accounted for as capital additions to oil and gas properties or as Lease operating expense, depending on the nature of the related expenditures.
	Contingencies. The Company is party to various legal and regulatory proceedings and commercial disputes arising in the normal course of business. The ultimate outcome of each of these matters cannot be absolutely determined, and in the event of a negative outcome as to any proceeding, the liability the Company may ultimately incur with respect to any such proceeding may be in excess of amounts currently accrued, if any. After considering the Company’s available insurance and, to the extent applicable, that of third parties, and the performance of contractual defense and indemnity rights and obligations, where applicable, the Company does not believe any such matter will have a material adverse effect on its financial position, results of operations or cash flows.

Equity

Equity	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Equity	'
	(10) Equity
	Earnings per Share. Basic earnings per share (“EPS”) is calculated by dividing net income (the numerator) by the weighted-average number of shares of common stock (excluding unvested restricted stock awards) outstanding during the period (the denominator). Diluted EPS incorporates the dilutive impact of outstanding stock options and unvested restricted stock awards using the treasury stock method.
	The following is a calculation of basic and diluted weighted average shares outstanding:
		Three Months Ended March 31,
		2014		2013
		(In thousands)
	Basic weighted average number of shares outstanding		61,380		52,733
	Dilution effect of stock option and restricted shares at the end of the period		167		348
	Diluted weighted average number of shares outstanding		61,547		53,081
	Anti-dilutive stock awards and shares		9		2
	Common Stock Offering. On April 23, 2013, the Company completed its public offering of 7,000,000 shares of common stock at a price to the public of $42.50 per share for net proceeds of approximately $286.3 million ($40.80 per share, net of underwriting discounts and commissions), including offering expenses and reimbursements by the underwriters of certain expenses incurred in connection with the offering. The Company also received net proceeds of approximately $43.0 million in connection with the underwriters’ full exercise of their over-allotment option to purchase 1,050,000 additional shares of common stock, which closed on April 29, 2013.

StockBased_Compensation_and_Em

Stock-Based Compensation and Employee Benefits	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation and Employee Benefits	'
	(11) Stock-Based Compensation and Employee Benefits
	Stock-based compensation expense includes the expense associated with restricted stock granted to employees and directors and the expense associated with the Performance Share Units (“PSUs”) granted to management. As of the indicated dates, stock-based compensation expense consisted of the following:
		Three Months Ended March 31,
		2014			2013
		(In thousands)
	Total stock-based compensation expense	$	3,481		$	2,738
	Capitalized in oil and gas properties		(123	)		(74	)
	Net stock-based compensation expense	$	3,358		$	2,664
	All stock-based compensation expense associated with restricted stock granted to employees and directors is recognized on a straight-line basis over the applicable remaining vesting period. For the three months ended March 31, 2014, the Company recorded compensation expense of approximately $2.7 million related to these equity awards. As of March 31, 2014, unrecognized stock-based compensation expense related to unvested restricted stock was approximately $17.8 million.
	Stock-based compensation expense associated with the PSUs granted to management is recognized over a three-year performance period. For the three months ended March 31, 2014, the Company recognized compensation expense of $0.8 million associated with the PSUs. At the current fair value as of March 31, 2014, and assuming the Board elects the maximum available payout of 200% for all PSU metrics, unrecognized stock-based compensation expense related to the PSUs was approximately $18.2 million. The Company’s total stock-based compensation expense will be measured and adjusted quarterly until settlement occurs, based on the Company’s performance, expected payout and quarter-end closing common stock prices. For a more detailed description of the Company’s PSU plans, including related performance conditions and structure, see the definitive proxy statement filed with respect to the Company’s 2014 annual meeting under the heading “Compensation Discussion and Analysis” and the Company’s 2013 Annual Report.
	Postretirement Health Care. Effective January 1, 2013, the Company enacted a postretirement medical benefit plan covering eligible employees and their eligible dependents. Upon enactment, the Company recognized a $0.3 million liability related to the prior service of employees which is included as a component of Other comprehensive income. The Company recognizes periodic postretirement benefits cost as a component of General and administrative costs. For the three months ended March 31, 2014, this expense was immaterial.

Guarantor_Subsidiaries

Guarantor Subsidiaries	3 Months Ended
	Mar. 31, 2014
Guarantees [Abstract]	'
Guarantor Subsidiaries	'
	(12) Guarantor Subsidiaries
	The Company’s Senior Notes are guaranteed by its wholly owned subsidiaries. Rosetta Resources Inc., as the parent company, has no independent assets or operations. The guarantees are full and unconditional and joint and several. In addition, there are no restrictions on the ability of the Company to obtain funds from its subsidiaries by dividend or loan. Finally, none of the Company’s subsidiaries has restricted assets that exceed 25% of net assets as of the most recent fiscal year which may not be transferred to the Company in the form of loans, advances or cash dividends by the subsidiaries without the consent of a third party.

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	(13) Subsequent Events
	On April 2, 2014, the Company entered into an amendment to its Credit Facility. Under this amendment, the Company’s borrowing base was increased from $800 million to $950 million and the committed amount under the Credit Facility was reconfirmed at $800 million with a maximum credit amount of $1.5 billion.
	On May 5, 2014, the Company redeemed its 9.500% Senior Notes prior to their scheduled maturity of April 15, 2018 with borrowings under the Company’s Credit Facility. The notes were redeemed for $210.6 million, which represented 100 percent of the principal amount, a make-whole premium of $9.5 million and $1.1 million of accrued and unpaid interest. The $9.5 million make-whole premium and $3.1 million of remaining unamortized debt issuance costs will be included in Other expense in the Company’s Consolidated Statement of Operations in the second quarter of 2014.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Recent Accounting Developments	'
	Recent Accounting Developments
	There have been no recently issued accounting developments that have been applied or may impact the Company in future periods.

Property_and_Equipment_Tables

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2014
Extractive Industries [Abstract]	'
Schedule of Total Property, Plant and Equipment, Net	'
	The Company’s Total property and equipment, net consists of the following:
			March 31, 2014			December 31, 2013
			(In thousands)
	Proved properties		$	4,387,172		$	3,951,397
	Unproved/unevaluated properties			727,051			755,438
	Gathering systems and compressor stations			204,944			168,730
	Other fixed assets			27,299			26,362
	Total			5,346,466			4,901,927
	Less: Accumulated depreciation, depletion and amortization			(2,094,737	)		(2,020,879	)
	Total property and equipment, net		$	3,251,729		$	2,881,048
Schedule of Consideration Paid Asset Acquired and Liabilities Assumed	'
	The final purchase price allocation for the 2013 Permian and Gates Ranch Acquisitions and the preliminary purchase price allocation for the 2014 Permian Acquisition, representing consideration paid, assets acquired and liabilities assumed as of the respective acquisition dates, are shown in the tables below.
	2013 Permian Acquisition and Gates Ranch Acquisition
			Final Total Purchase Price
			Allocation
			(in thousands)
	Cash consideration		$	953,242
	Fair value of assets acquired:
	Other fixed assets		$	600
	Oil and natural gas properties
	Proved properties			290,273
	Unproved/unevaluated properties			663,300
	Total assets acquired		$	954,173
	Fair value of liabilities assumed:
	Asset retirement obligations		$	931
	Net assets acquired		$	953,242
	2014 Permian Acquisition
			Preliminary Total Purchase Price
			Allocation
			(in thousands)
	Cash consideration		$	83,172
	Fair value of assets acquired:
	Oil and natural gas properties
	Proved properties		$	61,598
	Unproved/unevaluated properties			21,867
	Total assets acquired		$	83,465
	Fair value of liabilities assumed:
	Asset retirement obligations		$	293
	Net assets acquired		$	83,172
Schedule of Results of Operations at the Time of Transactions	'
	The pro forma information does not purport to represent what the Company’s results of operations would have been if the 2013 Permian Acquisition and Gates Acquisition had occurred on January 1, 2012 and the 2014 Permian Acquisition had occurred on January 1, 2013.
			Three Months Ended March 31,
			2014 (1)			2013
			(In thousands, except per share and share data)
	Total revenues		$	218,306		$	202,914
	Net income			36,147			51,860
	Earnings per share:
	Basic		$	0.59		$	0.85
	Diluted		$	0.59		$	0.85
	Weighted average shares outstanding:
	Basic			61,380			60,783
	Diluted			61,547			61,131
	-1	No pro forma adjustments were made related to the 2013 Permian Acquisition and Gates Acquisition for the period as the acquisitions and related financings are included in the Company’s historical results.

Commodity_Derivative_Contracts1

Commodity Derivative Contracts (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Schedule of Derivative Instruments	'
	As of March 31, 2014, the following derivative contracts were outstanding with associated notional volumes and average underlying prices that represent hedged prices of commodities at various market locations:
	Product	Settlement				Derivative	Notional			Total		Average		Average
		Period				Instrument	Daily			Notional		Floor/Fixed Prices		Ceiling Prices
							Volume			Volume		per Bbl		per Bbl
							(Bbls)			(Bbls)
	Crude oil		2014			Costless Collar		3,000			825,000	$	83.33	$	109.63
	Crude oil		2014			Swap		6,000			1,650,000		93.13
	Crude oil		2015			Swap		10,000			3,650,000		88.58
	Crude oil		2016			Swap		1,000			366,000		84.4
											6,491,000
	Product	Settlement				Derivative	Notional			Total		Average
		Period				Instrument	Daily			Notional		Fixed Prices
							Volume			Volume		per Bbl
							(Bbls)			(Bbls)
	NGL-Ethane		2014			Swap		4,500			1,237,500	$	13.21
	NGL-Propane		2014			Swap		2,785			765,875		44.71
	NGL-Isobutane		2014			Swap		930			255,750		61.26
	NGL-Normal Butane		2014			Swap		875			240,625		60.29
	NGL-Pentanes Plus		2014			Swap		910			250,250		84.97
	NGL-Ethane		2015			Swap		2,500			912,500		11.59
	NGL-Propane		2015			Swap		1,250			456,250		43.26
	NGL-Isobutane		2015			Swap		450			164,250		53.76
	NGL-Normal Butane		2015			Swap		400			146,000		53.76
	NGL-Pentanes Plus		2015			Swap		400			146,000		76.44
											4,575,000
	Product	Settlement				Derivative	Notional			Total		Average		Average
		Period				Instrument	Daily			Notional		Floor/Fixed Prices		Ceiling Prices
							Volume			Volume		per MMBtu		per MMBtu
							(MMBtu)			(MMBtu)
	Natural gas		2014			Costless Collar		50,000			13,750,000		3.6		4.94
	Natural gas		2015			Costless Collar		50,000			18,250,000		3.6		5.04
	Natural gas		2014			Swap		30,000			8,250,000		4.07
	Natural gas		2015			Swap		40,000			14,600,000		4.18
	Natural gas		2016			Swap		20,000			7,320,000		4.02
											62,170,000
Schedule of Derivative Instruments in Statement of Financial Position	'
	The following table sets forth information on the location and amounts of the Company’s derivative instrument fair values in the Consolidated Balance Sheet as of March 31, 2014 and December 31, 2013, respectively:
				Asset (Liability) Fair Value
				March 31, 2014			December 31, 2013
	Commodity derivative contracts	Location on Consolidated Balance Sheet		(In thousands)
	Oil	Derivative instruments—current assets		$	—		$	1,299
	Oil	Derivative instruments—non-current assets			1,055			2,117
	Oil	Derivative instruments—current liabilities			(10,837	)		(5,629	)
	Oil	Derivative instruments—non-current liabilities			(2,159	)		—
	NGL	Derivative instruments—current assets			37			2,834
	NGL	Derivative instruments—non-current assets			274			(129	)
	NGL	Derivative instruments—current liabilities			2,909			461
	NGL	Derivative instruments—non-current liabilities			299			(433	)
	Natural gas	Derivative instruments—current assets			—			174
	Natural gas	Derivative instruments—non-current assets			1,381			3,470
	Natural gas	Derivative instruments—current liabilities			(5,810	)		255
	Natural gas	Derivative instruments—non-current liabilities			1,422			—
	Total derivative fair value, net, not designated as hedging instruments			$	(11,429	)	$	4,419
Schedule of Derivative Gains and Losses in Consolidated Statement of Operation	'
	The following table sets forth information on the location and amounts of derivative gains and losses in the Consolidated Statement of Operations for the three months ended March 31, 2014 and 2013, respectively:
				Three Months Ended March 31,
	Location on Consolidated			2014			2013
	Statement of Operations	Description of (Loss) Gain		(In thousands)
	Derivative instruments	(Loss) gain recognized in income			(7,937	)		2,002
		Realized (loss) gain recognized in income		$	(7,937	)	$	2,002
	Derivative instruments	Loss recognized in income due to changes in fair value		$	(15,848	)	$	(13,546	)
	Derivative instruments	Loss reclassified from Accumulated OCI			—			(425	)
		Unrealized loss recognized in income		$	(15,848	)	$	(13,971	)
		Total commodity derivative loss recognized in income		$	(23,785	)	$	(11,969	)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis	'
	The following table sets forth by level within the fair value hierarchy the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis for the respective period:
			Fair value as of March 31, 2014
			Level 1			Level 2			Level 3			Netting (1)			Total
			(In thousands)
	Assets:
	Money market funds		$	—		$	1,035		$	—		$	—		$	1,035
	Commodity derivative contracts			—			—			13,992			(11,245	)		2,747
	Liabilities:
	Commodity derivative contracts			—			—			(25,421	)		11,245			(14,176	)
	Total fair value		$	—		$	1,035		$	(11,429	)	$	—		$	(10,394	)
			Fair value as of December 31, 2013
			Level 1			Level 2			Level 3			Netting (1)			Total
			(In thousands)
	Assets:
	Money market funds		$	—		$	1,035		$	—		$	—		$	1,035
	Commodity derivative contracts			—			—			21,675			(11,910	)		9,765
	Liabilities:
	Commodity derivative contracts			—			—			(17,256	)		11,910			(5,346	)
	Total fair value		$	—		$	1,035		$	4,419		$	—		$	5,454
	-1	Represents the impact of netting commodity derivative assets and liabilities with counterparties where the Company has the contractual right and intends to net settle. No margin or collateral balances are deposited with counterparties and as such, gross amounts are offset to determine the net amounts presented in the Consolidated Balance Sheet.
Schedule of Valuation Process and Unobservable Inputs	'
	The following table presents a range of the unobservable inputs provided by the Company’s third-party provider utilized in the fair value measurements of the Company’s assets and liabilities classified as Level 3 instruments as of March 31, 2014 (in thousands):
			Asset						Range						Weighted
	Level 3 Instrument		(Liability)			Valuation Technique		Unobservable Input	Minimum			Maximum			Average
	Oil swaps		$	(12,050	)	Discounted cash flow		Forward price curve-swaps	$	82.94		$	101.36		$	91.81
	Oil costless collars			110		Option model		Forward price curve- costless collar option value		(1.45	)		2.28			0.13
	NGL swaps			5,263		Discounted cash flow		Forward price curve-swaps		0.27			1.31			0.55
	NGL swaps			(1,744	)	Discounted cash flow		Forward price curve-swaps		1			2.17			1.3
	Natural gas swaps			(3,017	)	Discounted cash flow		Forward price curve-swaps		3.95			4.52			4.24
	Natural gas swaps			703		Discounted cash flow		Forward price curve-swaps		3.87			4.68			4.13
	Natural gas costless collars			(1,031	)	Option model		Forward price curve- costless collar option value		(0.28	)		0.12			(0.07	)
	Natural gas costless collars			337		Option model		Forward price curve- costless collar option value		(0.37	)		0.29			0.02
	Total		$	(11,429	)
Schedule of Fair Value Assets and Liabilities Classified	'
	The tables below present reconciliations of financial assets and liabilities classified as Level 3 in the fair value hierarchy during the indicated periods.
			Derivative
			Asset (Liability)
			(In thousands)
	Balance at January 1, 2014		$	4,419
	Total Gains or (Losses) (Realized or Unrealized):
	Included in Earnings			(23,785	)
	Purchases, Issuances and Settlements:
	Settlements			7,937
	Transfers in and out of Level 3			—
	Balance at March 31, 2014		$	(11,429	)
			Derivative
			Asset (Liability)
			(In thousands)
	Balance at January 1, 2013		$	20,664
	Total Gains or (Losses) (Realized or Unrealized):
	Included in Earnings			(11,544	)
	Purchases, Issuances and Settlements:
	Settlements			(2,002	)
	Transfers in and out of Level 3			—
	Balance at March 31, 2013		$	7,118

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	3 Months Ended
	Mar. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]	'
Schedule of Asset Retirement Obligations	'
	Activity related to the Company’s ARO is as follows:
		Three Months Ended
		March 31, 2014
		(In thousands)
	ARO as of December 31, 2013	$	13,057
	Liabilities incurred during period		810
	Liabilities settled during period		—
	Accretion expense		232
	ARO as of March 31, 2014	$	14,099

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Future Obligations Under Firm Gas and Oil Transportation Agreements	'
	Future obligations under firm oil and natural gas transportation and processing agreements as of March 31, 2014 are as follows:
		March 31, 2014
		(In thousands)
	2015	$	34,313
	2016		33,844
	2017		33,388
	2018		29,839
	2019		27,580
	Thereafter		76,508
	Total future obligations	$	235,472

Equity_Tables

Equity (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Schedule of Basic and Diluted Weighted Average Shares Outstanding	'
	The following is a calculation of basic and diluted weighted average shares outstanding:
		Three Months Ended March 31,
		2014		2013
		(In thousands)
	Basic weighted average number of shares outstanding		61,380		52,733
	Dilution effect of stock option and restricted shares at the end of the period		167		348
	Diluted weighted average number of shares outstanding		61,547		53,081
	Anti-dilutive stock awards and shares		9		2

StockBased_Compensation_and_Em1

Stock-Based Compensation and Employee Benefits (Tables)	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Schedule Of Stock-Based Compensation Expense	'
	As of the indicated dates, stock-based compensation expense consisted of the following:
		Three Months Ended March 31,
		2014			2013
		(In thousands)
	Total stock-based compensation expense	$	3,481		$	2,738
	Capitalized in oil and gas properties		(123	)		(74	)
	Net stock-based compensation expense	$	3,358		$	2,664

Property_and_Equipment_Schedul

Property and Equipment - Schedule of Total Property, Plant and Equipment, Net (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Capitalized Costs, Oil and Gas Producing Activities, Net [Abstract]	'	'
Proved properties	$4,387,172	$3,951,397
Unproved/unevaluated properties	727,051	755,438
Gathering systems and compressor stations	204,944	168,730
Other fixed assets	27,299	26,362
Total	5,346,466	4,901,927
Less: Accumulated depreciation, depletion and amortization	-2,094,737	-2,020,879
Total property and equipment, net	$3,251,729	$2,881,048

Property_and_Equipment_Additio

Property and Equipment - Additional Information (Detail) (USD $)

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

3 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Apr. 15, 2010

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Bridge Loan [Member]

Senior Notes [Member]

Adjusted For Basis And Quality Differentials [Member]

Delaware Basin [Member]

2014 Permian Acquisition [Member]

Eagle Ford Shale [Member]

Eagle Ford Shale [Member]

Texas [Member]

Well

South Texas Gates Ranch [Member]

acre

Property, Plant and Equipment [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Acquisition date

'

'

'

'

'

'

'

28-Feb-14

'

'

'

'

Acquisition effective date

'

'

'

'

'

'

'

1-Dec-13

'

'

'

1-Jan-13

Payments to acquire businesses

'

'

'

'

'

'

'

$83.20

'

'

'

$825.20

Number of wells acquired

'

'

'

'

'

'

'

13

'

'

'

'

Number of operating wells

'

'

'

'

'

'

'

11

'

'

'

'

Area of land acquired

'

'

'

'

'

'

'

5,034

'

'

'

'

Acquisition date

'

'

'

'

'

'

'

'

'

5-Jun-13

'

14-May-13

Percentage of working interests acquired

'

'

'

'

'

'

'

'

'

10.00%

100.00%

'

Working interest acquisition, total consideration

'

'

'

'

'

'

'

'

'

128.1

'

'

Transaction cost

31

'

'

'

'

'

'

'

'

'

'

'

Commitment fees and related expenses

'

'

'

'

5.6

'

'

'

'

'

'

'

Debt issuance costs

'

'

'

'

'

10

'

'

'

'

'

'

Senior notes, percentage

'

'

'

9.50%

'

5.63%

'

'

'

'

'

'

Equity issuance costs and related expenses

13.1

'

'

'

'

'

'

'

'

'

'

'

Acquisition related fees, included in general and administrative costs

2.3

'

'

'

'

'

'

'

'

'

'

'

Increase in total revenue

'

'

'

'

'

'

'

'

24.5

'

'

'

Increase in operating income

'

'

'

'

'

'

'

'

16.8

'

'

'

Capitalized internal cost

1.6

2.1

'

'

'

'

'

'

'

'

'

'

Oil and natural gas properties excluded from amortization, full cost method

$727.10

'

$755.40

'

'

'

'

'

'

'

'

'

West Texas Intermediate oil price (per Bbl)

'

'

'

'

'

'

94.92

'

'

'

'

'

Henry Hub natural gas price (per MMBtu)

'

'

'

'

'

'

3.99

'

'

'

'

'

Property_and_Equipment_Schedul1

Property and Equipment - Schedule of Consideration Paid Asset Acquired and Liabilities Assumed (Detail) (Level 3 [Member], USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
2013 Permian Acquisition and Gates Ranch Acquisition [Member]	'
Property, Plant and Equipment [Line Items]	'
Cash consideration	$953,242
Fair value of assets acquired:	'
Other fixed assets	600
Oil and natural gas properties	'
Proved properties	290,273
Unproved/unevaluated properties	663,300
Total assets acquired	954,173
Fair value of liabilities assumed:	'
Asset retirement obligations	931
Net assets acquired	953,242
2014 Permian Acquisition [Member]	'
Property, Plant and Equipment [Line Items]	'
Cash consideration	83,172
Oil and natural gas properties	'
Proved properties	61,598
Unproved/unevaluated properties	21,867
Total assets acquired	83,465
Fair value of liabilities assumed:	'
Asset retirement obligations	293
Net assets acquired	$83,172

Property_and_Equipment_Schedul2

Property and Equipment - Schedule of Results of Operations at the Time of Transactions (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Property Plant And Equipment Useful Life And Values [Abstract]	'	'
Total revenues	$218,306	$202,914
Net income	$36,147	$51,860
Earnings per share:	'	'
Basic	$0.59	$0.85
Diluted	$0.59	$0.85
Weighted average shares outstanding:	'	'
Basic	61,380	60,783
Diluted	61,547	61,131

Commodity_Derivative_Contracts2

Commodity Derivative Contracts - Schedule of Derivative Instruments (Detail)	Mar. 31, 2014
	MMBTU
Natural Gas [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Total Notional Volume MMBtu	62,170,000
NGL-Product [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Total Notional Volume	4,575,000
Crude Oil [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Total Notional Volume	6,491,000
Costless Collar [Member] | 2014 Settlement Period [Member] | Natural Gas [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume MMBtu	50,000
Total Notional Volume MMBtu	13,750,000
Average Fixed Prices per Bbl	3.6
Average Ceiling Prices per Bbl	4.94
Costless Collar [Member] | 2014 Settlement Period [Member] | Crude Oil [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	3,000
Total Notional Volume	825,000
Average Fixed Prices per Bbl	83.33
Average Ceiling Prices per Bbl	109.63
Costless Collar [Member] | 2015 Settlement Period [Member] | Natural Gas [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume MMBtu	50,000
Total Notional Volume MMBtu	18,250,000
Average Fixed Prices per Bbl	3.6
Average Ceiling Prices per Bbl	5.04
Swap [Member] | 2014 Settlement Period [Member] | Natural Gas [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume MMBtu	30,000
Total Notional Volume MMBtu	8,250,000
Average Fixed Prices per Bbl	4.07
Swap [Member] | 2014 Settlement Period [Member] | NGL-Ethane [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	4,500
Total Notional Volume	1,237,500
Average Fixed Prices per Bbl	13.21
Swap [Member] | 2014 Settlement Period [Member] | NGL-Propane [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	2,785
Total Notional Volume	765,875
Average Fixed Prices per Bbl	44.71
Swap [Member] | 2014 Settlement Period [Member] | NGL-Isobutane [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	930
Total Notional Volume	255,750
Average Fixed Prices per Bbl	61.26
Swap [Member] | 2014 Settlement Period [Member] | NGL-Normal Butane [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	875
Total Notional Volume	240,625
Average Fixed Prices per Bbl	60.29
Swap [Member] | 2014 Settlement Period [Member] | NGL-Pentanes Plus [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	910
Total Notional Volume	250,250
Average Fixed Prices per Bbl	84.97
Swap [Member] | 2014 Settlement Period [Member] | Crude Oil [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	6,000
Total Notional Volume	1,650,000
Average Fixed Prices per Bbl	93.13
Swap [Member] | 2015 Settlement Period [Member] | Natural Gas [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume MMBtu	40,000
Total Notional Volume MMBtu	14,600,000
Average Fixed Prices per Bbl	4.18
Swap [Member] | 2015 Settlement Period [Member] | NGL-Ethane [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	2,500
Total Notional Volume	912,500
Average Fixed Prices per Bbl	11.59
Swap [Member] | 2015 Settlement Period [Member] | NGL-Propane [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	1,250
Total Notional Volume	456,250
Average Fixed Prices per Bbl	43.26
Swap [Member] | 2015 Settlement Period [Member] | NGL-Isobutane [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	450
Total Notional Volume	164,250
Average Fixed Prices per Bbl	53.76
Swap [Member] | 2015 Settlement Period [Member] | NGL-Normal Butane [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	400
Total Notional Volume	146,000
Average Fixed Prices per Bbl	53.76
Swap [Member] | 2015 Settlement Period [Member] | NGL-Pentanes Plus [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	400
Total Notional Volume	146,000
Average Fixed Prices per Bbl	76.44
Swap [Member] | 2015 Settlement Period [Member] | Crude Oil [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	10,000
Total Notional Volume	3,650,000
Average Fixed Prices per Bbl	88.58
Swap [Member] | 2016 Settlement Period [Member] | Natural Gas [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume MMBtu	20,000
Total Notional Volume MMBtu	7,320,000
Average Fixed Prices per Bbl	4.02
Swap [Member] | 2016 Settlement Period [Member] | Crude Oil [Member]	'
Derivative Instruments, Gain (Loss) [Line Items]	'
Notional Daily Volume	1,000
Total Notional Volume	366,000
Average Fixed Prices per Bbl	84.4

Commodity_Derivative_Contracts3

Commodity Derivative Contracts - Schedule of Derivative Instruments in Statement of Financial Position (Detail) (USD $)	Mar. 31, 2014	Mar. 31, 2013
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	($11,429)	'
Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	-11,429	4,419
Commodity Contracts [Member] | Current Assets [Member] | Crude Oil [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	'	1,299
Commodity Contracts [Member] | Current Assets [Member] | NGL [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	37	2,834
Commodity Contracts [Member] | Current Assets [Member] | Natural Gas [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	'	174
Commodity Contracts [Member] | Non-Current Assets [Member] | Crude Oil [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	1,055	2,117
Commodity Contracts [Member] | Non-Current Assets [Member] | NGL [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	274	-129
Commodity Contracts [Member] | Non-Current Assets [Member] | Natural Gas [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	1,381	3,470
Commodity Contracts [Member] | Current Liabilities [Member] | Crude Oil [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	-10,837	-5,629
Commodity Contracts [Member] | Current Liabilities [Member] | NGL [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	2,909	461
Commodity Contracts [Member] | Current Liabilities [Member] | Natural Gas [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	-5,810	255
Commodity Contracts [Member] | Noncurrent Liabilities [Member] | Crude Oil [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	-2,159	'
Commodity Contracts [Member] | Noncurrent Liabilities [Member] | NGL [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	299	-433
Commodity Contracts [Member] | Noncurrent Liabilities [Member] | Natural Gas [Member] | Derivatives Not Designated As Hedging Instruments [Member]	'	'
Derivatives, Fair Value [Line Items]	'	'
Fair value of derivative instruments	$1,422	'

Commodity_Derivative_Contracts4

Commodity Derivative Contracts - Schedule of Derivative Gains and Losses in Consolidated Statement of Operations (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'
Realized (loss) gain recognized in income	($7,937)	$2,002
Unrealized loss recognized in income	-15,848	-13,971
Total commodity derivative loss recognized in income	-23,785	-11,969
Derivative Instruments [Member]	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'
(Loss) gain recognized in income	-7,937	2,002
Loss recognized in income due to changes in fair value	-15,848	-13,546
Loss reclassified from Accumulated OCI	'	($425)

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	($10,394)	$5,454
Money Market Funds Asset (Liability) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	1,035	1,035
Commodity Derivative Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	2,747	9,765
Fair value of assets and liabilities measured on recurring basis	-14,176	-5,346
Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	'	'
Level 1 [Member] | Money Market Funds Asset (Liability) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	'	'
Level 1 [Member] | Commodity Derivative Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	'	'
Fair value of assets and liabilities measured on recurring basis	'	'
Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	1,035	1,035
Level 2 [Member] | Money Market Funds Asset (Liability) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	1,035	1,035
Level 2 [Member] | Commodity Derivative Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	'	'
Fair value of assets and liabilities measured on recurring basis	'	'
Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	-11,429	4,419
Level 3 [Member] | Money Market Funds Asset (Liability) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	'	'
Level 3 [Member] | Commodity Derivative Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	13,992	21,675
Fair value of assets and liabilities measured on recurring basis	-25,421	-17,256
Netting [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	'	'
Netting [Member] | Money Market Funds Asset (Liability) [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	'	'
Netting [Member] | Commodity Derivative Contracts [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of assets and liabilities measured on recurring basis	-11,245	-11,910
Fair value of assets and liabilities measured on recurring basis	$11,245	$11,910

Fair_Value_Measurements_Schedu1

Fair Value Measurements - Schedule of Valuation Process and Unobservable Inputs (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Fair Value, Derivative Asset (Liability)	($11,429)
Bbl [Member] | Derivative Liabilities [Member] | Crude Oil [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Fair Value, Derivative Asset (Liability)	-12,050
Derivative assets, Valuation Technique	'Discounted cash flow
Unobservable Input	'Forward price curve-swaps
Bbl [Member] | Derivative Assets [Member] | Crude Oil [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Fair Value, Derivative Asset (Liability)	110
Derivative assets, Valuation Technique	'Option model
Unobservable Input	'Forward price curve- costless collar option value
MMBtu [Member] | Derivative Liabilities [Member] | NGL [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Fair Value, Derivative Asset (Liability)	-1,744
Derivative assets, Valuation Technique	'Discounted cash flow
Unobservable Input	'Forward price curve-swaps
MMBtu [Member] | Derivative Liabilities [Member] | Natural Gas [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Fair Value, Derivative Asset (Liability)	-1,031
Derivative assets, Valuation Technique	'Option model
Unobservable Input	'Forward price curve- costless collar option value
MMBtu [Member] | Derivative Liabilities [Member] | Natural Gas [Member] | Natural Gas Swaps [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Fair Value, Derivative Asset (Liability)	-3,017
Derivative assets, Valuation Technique	'Discounted cash flow
Unobservable Input	'Forward price curve-swaps
MMBtu [Member] | Derivative Assets [Member] | NGL [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Fair Value, Derivative Asset (Liability)	5,263
Derivative assets, Valuation Technique	'Discounted cash flow
Unobservable Input	'Forward price curve-swaps
MMBtu [Member] | Derivative Assets [Member] | Natural Gas [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Fair Value, Derivative Asset (Liability)	337
Derivative assets, Valuation Technique	'Option model
Unobservable Input	'Forward price curve- costless collar option value
MMBtu [Member] | Derivative Assets [Member] | Natural Gas [Member] | Natural Gas Swaps [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Fair Value, Derivative Asset (Liability)	$703
Derivative assets, Valuation Technique	'Discounted cash flow
Unobservable Input	'Forward price curve-swaps
Minimum [Member] | Bbl [Member] | Derivative Liabilities [Member] | Crude Oil [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	82.94
Minimum [Member] | Bbl [Member] | Derivative Assets [Member] | Crude Oil [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	-1.45
Minimum [Member] | MMBtu [Member] | Derivative Liabilities [Member] | NGL [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	1
Minimum [Member] | MMBtu [Member] | Derivative Liabilities [Member] | Natural Gas [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	-0.28
Minimum [Member] | MMBtu [Member] | Derivative Liabilities [Member] | Natural Gas [Member] | Natural Gas Swaps [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	3.95
Minimum [Member] | MMBtu [Member] | Derivative Assets [Member] | NGL [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	0.27
Minimum [Member] | MMBtu [Member] | Derivative Assets [Member] | Natural Gas [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	-0.37
Minimum [Member] | MMBtu [Member] | Derivative Assets [Member] | Natural Gas [Member] | Natural Gas Swaps [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	3.87
Maximum [Member] | Bbl [Member] | Derivative Liabilities [Member] | Crude Oil [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	101.36
Maximum [Member] | Bbl [Member] | Derivative Assets [Member] | Crude Oil [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	2.28
Maximum [Member] | MMBtu [Member] | Derivative Liabilities [Member] | NGL [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	2.17
Maximum [Member] | MMBtu [Member] | Derivative Liabilities [Member] | Natural Gas [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	0.12
Maximum [Member] | MMBtu [Member] | Derivative Liabilities [Member] | Natural Gas [Member] | Natural Gas Swaps [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	4.52
Maximum [Member] | MMBtu [Member] | Derivative Assets [Member] | NGL [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	1.31
Maximum [Member] | MMBtu [Member] | Derivative Assets [Member] | Natural Gas [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	0.29
Maximum [Member] | MMBtu [Member] | Derivative Assets [Member] | Natural Gas [Member] | Natural Gas Swaps [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	4.68
Weighted Average [Member] | Bbl [Member] | Derivative Liabilities [Member] | Crude Oil [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	91.81
Weighted Average [Member] | Bbl [Member] | Derivative Assets [Member] | Crude Oil [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	0.13
Weighted Average [Member] | MMBtu [Member] | Derivative Liabilities [Member] | NGL [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	1.3
Weighted Average [Member] | MMBtu [Member] | Derivative Liabilities [Member] | Natural Gas [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	-0.07
Weighted Average [Member] | MMBtu [Member] | Derivative Liabilities [Member] | Natural Gas [Member] | Natural Gas Swaps [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	4.24
Weighted Average [Member] | MMBtu [Member] | Derivative Assets [Member] | NGL [Member] | Swap [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	0.55
Weighted Average [Member] | MMBtu [Member] | Derivative Assets [Member] | Natural Gas [Member] | Costless Collar [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	0.02
Weighted Average [Member] | MMBtu [Member] | Derivative Assets [Member] | Natural Gas [Member] | Natural Gas Swaps [Member]	'
Fair Value Assets And Liabilities Measured On Unobservable Inputs [Line Items]	'
Forward Price Curve	4.13

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair value of its derivative instruments	$0.20
Fair market value of total debt	1,606
Carrying amount of debt	$1,560

Fair_Value_Measurements_Schedu2

Fair Value Measurements - Schedule of Fair Value Assets and Liabilities Classified (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'
Settlements	$7,937	($2,002)
Derivatives Asset (Liability) [Member]	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'
Balance, Beginning	4,419	20,664
Included in Earnings	-23,785	-11,544
Settlements	7,937	-2,002
Transfers in and out of Level 3	'	'
Balance, Ending	($11,429)	$7,118

Asset_Retirement_Obligations_S

Asset Retirement Obligations - Schedule of Asset Retirement Obligations (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]	'
ARO at the beginning of the period	$13,057
Liabilities incurred during period	810
Liabilities settled during period	'
Accretion expense	232
ARO at the end of the period	$14,099

Asset_Retirement_Obligations_A

Asset Retirement Obligations - Additional Information (Detail) (USD $)	Mar. 31, 2014
In Millions, unless otherwise specified
Asset Retirement Obligation Disclosure [Abstract]	'
Current portion of ARO	$4
Long-term portion of ARO	$10.10

Debt_and_Credit_Agreements_Add

Debt and Credit Agreements - Additional Information (Detail) (USD $)

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Mar. 31, 2014

Apr. 15, 2010

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Apr. 15, 2010

Mar. 31, 2014

2-May-13

Mar. 31, 2014

Nov. 15, 2013

Minimum [Member]

Maximum [Member]

London Interbank Offered Rate (LIBOR) [Member]

Alternative Base Rate [Member]

Alternative Base Rate [Member]

Amended and Restated Senior Revolving Credit Agreement [Member]

Amended and Restated Senior Revolving Credit Agreement [Member]

Credit Facilities [Member]

9.500% Senior Notes due 2018 [Member]

9.500% Senior Notes due 2018 [Member]

5.625% Senior Notes due 2021 [Member]

5.625% Senior Notes due 2021 [Member]

5.875% Senior Notes due 2022 [Member]

5.875% Senior Notes due 2022 [Member]

Ratio

Maximum [Member]

Minimum [Member]

Maximum [Member]

London Interbank Offered Rate (LIBOR) [Member]

Minimum [Member]

Line of Credit Facility [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount outstanding

'

'

'

'

'

'

'

$60

'

'

'

'

'

'

'

'

Available borrowing capacity

'

'

'

'

'

'

'

740

'

'

'

'

'

'

'

'

Debt instrument, interest rate, stated percentage

'

9.50%

'

'

2.50%

0.50%

1.50%

'

1.50%

'

'

'

'

5.63%

'

5.88%

Weighted average borrowing rate under Restated Revolver

4.38%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total interest expense and commitment fees

'

'

'

'

'

'

'

'

'

0.8

'

'

'

'

'

'

Pre-tax SEC PV-10 reserve value, percentage

80.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Pledge of membership and limited partnership interests percentage

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current ratio

'

'

0.01

'

'

'

'

'

'

'

'

'

'

'

'

'

Leverage ratio

'

'

'

0.04

'

'

'

'

'

'

'

'

'

'

'

'

Current ratio

2.60%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Leverage ratio

2.60%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Senior notes

'

'

'

'

'

'

'

'

'

'

'

200

'

'

'

'

Debt maturity date

'

'

'

'

'

'

'

'

'

'

'Senior Notes due 2018

'

'Senior Notes due 2021

'

'Senior Notes due 2022

'

Redemption term of long-term debt

'

'

'

'

'

'

'

'

'

'

'104.75% of the principal amount, plus accrued and unpaid interest

'

'

'

'

'

Issuance of aggregate principal amount

'

'

'

'

'

'

'

'

'

'

'

'

'

700

'

600

Total outstanding borrowings

$1,560

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average borrowing rate

6.26%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'	'	'
Effective tax rate	35.20%	33.40%	'
Unrecognized tax benefits	$0	'	$0
Deferred tax liability	$145,998,000	'	$136,407,000

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
Oil and Gas Delivery Commitments and Contracts [Line Items]	'
Accrued deficiency fees	$2.40
Outstanding commitments	23.3
Minimum remaining contractual commitment	$7.80
Oil Commitments (MMBbls) [Member]	'
Oil and Gas Delivery Commitments and Contracts [Line Items]	'
Oil and gas delivery transportation commitments	4.5
Natural Gas Commitments (MMBtus) [Member]	'
Oil and Gas Delivery Commitments and Contracts [Line Items]	'
Oil and gas delivery transportation commitments	321,000,000

Commitments_and_Contingencies_2

Commitments and Contingencies - Future Obligations Under Firm Gas and Oil Transportation Agreements (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Oil And Gas Delivery Commitments And Contracts Additional Information [Abstract]	'
2015	$34,313
2016	33,844
2017	33,388
2018	29,839
2019	27,580
Thereafter	76,508
Total future obligations	$235,472

Equity_Schedule_of_Basic_and_D

Equity - Schedule of Basic and Diluted Weighted Average Shares Outstanding (Detail)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Equity [Abstract]	'	'
Basic weighted average number of shares outstanding	61,380	52,733
Dilution effect of stock option and restricted shares at the end of the period	167	348
Diluted weighted average number of shares outstanding	61,547	53,081
Anti-dilutive stock awards and shares	9	2

Equity_Additional_Information_

Equity - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014
Equity [Line Items]	'
Common stock price per share	$42.50
Underwriting discount and structuring fee per share, net	$40.80
Underwriters Overallotment Option [Member]	'
Equity [Line Items]	'
Public offering of common stock	1,050,000
Common Stock [Member]	'
Equity [Line Items]	'
Public offering of common stock	7,000,000
Net proceeds from equity issue	$286.30
Common Stock [Member] | Underwriters Overallotment Option [Member]	'
Equity [Line Items]	'
Net proceeds from equity issue	$43

StockBased_Compensation_and_Em2

Stock-Based Compensation and Employee Benefits - Schedule of Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'
Total stock-based compensation expense	$3,481	$2,738
Capitalized in oil and gas properties	-123	-74
Net stock-based compensation expense	$3,358	$2,664

StockBased_Compensation_and_Em3

Stock-Based Compensation and Employee Benefits - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock compensation expense recorded	$3,358,000	$2,664,000
Stock-based compensation expense associated with PSU	3,481,000	2,738,000
Postretirement Health Care Plans [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Liability related to prior service of employees	300,000	'
Employee Stock Option [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Stock compensation expense recorded	2,700,000	'
Unrecognized compensation expense	17,800,000	'
Performance Shares [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Unrecognized compensation expense	18,200,000	'
Stock-based compensation expense associated with PSU	$800,000	'
PSUs performance period, in years	'3 years	'
Number of shares vested range, percentage of targeted amounts	200.00%	'

Guarantor_Subsidiaries_Additio

Guarantor Subsidiaries - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2014
Guarantees [Abstract]	'
Number of subsidiaries with restricted assets that exceed 25% of net assets	'None
Maximum percentage of non-transferrable net assets	25.00%

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (Subsequent Event [Member], USD $)	Apr. 02, 2014	5-May-14	5-May-14
		9.500% Senior Notes due 2018 [Member]	9.500% Senior Notes due 2018 [Member]
			Accounts Payable and Accrued Liabilities [Member]
Subsequent Event [Line Items]	'	'	'
Current borrowing base	$800,000,000	'	'
Borrowing base increased	950,000,000	'	'
Maximum credit amount increased under credit agreement	1,500,000,000	'	'
Scheduled maturity date of debt instrument	'	15-Apr-18	'
Redemption of debt instrument	'	210,600,000	'
Redemption of debt instrument (Make-whole premium)	'	9,500,000	'
Accrued and unpaid interest	'	'	1,100,000
Debt instrument, unamortized premium	'	$3,100,000	'
Percentage of the principal amount redeemed	'	100.00%	'