Legacy Reserves 10-Q 31 Oct 14 2014 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 30, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'LEGACY RESERVES LP	'
Entity Central Index Key	'0001358831	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	69,165,815

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash	$2,998	$2,584
Accounts receivable, net:	'	'
Oil and natural gas	67,687	47,429
Joint interest owners	23,217	16,532
Other	400	626
Fair value of derivatives (Notes 6 and 7)	26,759	3,801
Prepaid expenses and other current assets	5,445	3,727
Total current assets	126,506	74,699
Oil and natural gas properties using the successful efforts method, at cost:	'	'
Proved properties	2,903,267	2,265,788
Unproved properties	81,634	58,392
Accumulated depletion, depreciation, amortization and impairment	-899,373	-788,751
Oil and natural gas properties using the successful efforts method, at cost	2,085,528	1,535,429
Other property and equipment, net of accumulated depreciation and amortization of $7,100 and $6,053, respectively	3,693	3,688
Operating rights, net of amortization of $4,387 and $4,024, respectively	2,629	2,992
Fair value of derivatives (Notes 6 and 7)	11,678	21,292
Other assets, net of amortization of $11,882 and $10,097, respectively	24,765	17,641
Investments in equity method investees	3,099	4,092
Total assets	2,257,898	1,659,833
Current liabilities:	'	'
Accounts payable	1,328	6,016
Accrued oil and natural gas liabilities (Note 1)	88,141	63,161
Fair value of derivatives (Notes 6 and 7)	2,437	10,060
Asset retirement obligation (Note 8)	2,610	2,610
Other (Notes 2 and 10)	28,910	12,043
Total current liabilities	123,426	93,890
Long-term debt (Note 2)	1,199,227	878,693
Asset retirement obligation (Note 8)	222,079	173,176
Fair value of derivatives (Notes 6 and 7)	280	2,119
Other long-term liabilities	1,924	1,559
Total liabilities	1,546,936	1,149,437
Commitments and contingencies (Note 5)	'	'
Partners' equity (Note 9):	'	'
Limited partners' equity - 57,405,398 and 57,280,049 units issued and outstanding at June 30, 2014 and December 31, 2013	450,617	510,322
General partner's equity (approximately 0.03%)	78	74
Total partners' equity	710,962	510,396
Total liabilities and partners' equity	2,257,898	1,659,833
Incentive distribution equity - 100,000 units issued and outstanding at September 30, 2014	'	'
Partners' equity (Note 9):	'	'
Incentive distribution equity - 100,000 units issued and outstanding at September 30, 2014	30,814	0
Series A Preferred equity - 2,300,000 units issued and outstanding at September 30, 2014	'	'
Partners' equity (Note 9):	'	'
Preferred equity	55,192	0
Series B Preferred equity - 7,200,000 units issued and outstanding at September 30, 2014	'	'
Partners' equity (Note 9):	'	'
Preferred equity	$174,261	$0

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	9 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Other property and equipment, accumulated depreciation and amortization	$7,100	$6,053
Operating rights, amortization	4,387	4,024
Other assets, amortization	$11,882	$10,097
Limited partners' equity, units issued (in shares)	57,409,784	57,280,049
Limited partners' equity, units outstanding (in shares)	57,409,784	57,280,049
General partner's equity, percent	0.03%	0.03%
Incentive Distribution Equity	'	'
Incentive distribution equity, units issued (in shares)	100,000	0
Incentive distribution equity, units outstanding (in shares)	100,000	0
Preferred Unit Series A	'	'
Preferred equity, units outstanding (in shares)	2,300,000	0
Preferred equity, units outstanding (in shares)	2,300,000	0
Preferred Unit Series B	'	'
Preferred equity, units outstanding (in shares)	7,200,000	0
Preferred equity, units outstanding (in shares)	7,200,000	0

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues:	'	'	'	'
Oil sales	$105,640	$116,396	$316,426	$304,606
Natural gas liquids (NGL) sales	10,413	3,686	19,482	10,188
Natural gas sales	33,623	16,101	76,786	48,654
Total revenues	149,676	136,183	412,694	363,448
Expenses:	'	'	'	'
Oil and natural gas production	55,491	39,701	143,834	112,236
Production and other taxes	7,742	8,385	24,292	22,083
General and administrative	8,325	7,933	30,781	21,279
Depletion, depreciation, amortization and accretion	48,016	37,717	120,250	118,482
Impairment of long-lived assets	4,785	835	8,583	23,352
(Gain) loss on disposal of assets	-1,683	758	-3,235	493
Total expenses	122,676	95,329	324,505	297,925
Operating income	27,000	40,854	88,189	65,523
Other income (expense):	'	'	'	'
Interest income	223	227	662	568
Interest expense (Notes 2, 6 and 7)	-19,083	-14,206	-49,247	-36,104
Equity in income of equity method investees	126	172	309	357
Net gains (losses) on commodity derivatives (Notes 6 and 7)	55,994	-30,424	8,675	-18,098
Other	-166	-16	137	-11
Income (loss) before income taxes	64,094	-3,393	48,725	12,235
Income tax expense	-278	-29	-870	-608
Net income (loss)	63,816	-3,422	47,855	11,627
Distributions to Preferred unitholders	-4,750	0	-6,944	0
Net income (loss) attributable to unitholders	$59,066	($3,422)	$40,911	$11,627
Income (loss) per unit - basic (Note 9) (in dollars per share)	$1.03	($0.06)	$0.71	$0.20
Income (loss) per unit - diluted (Note 9) (in dollars per share)	$1.02	($0.06)	$0.71	$0.20
Weighted average number of units used in computing net income per unit -	'	'	'	'
Basic (in shares)	57,406	57,275	57,363	57,200
Diluted (in shares)	57,643	57,275	57,523	57,295

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Unitholders Equity (USD $)	Total	Series A Preferred Equity	Series B Preferred Equity	Preferred Equity	Preferred Equity	Preferred Equity	Preferred Equity	Incentive Distribution Equity	Unitholders' Equity	Unitholders' Equity	Unitholders' Equity
In Thousands, except Share data, unless otherwise specified	USD ($)			USD ($)	Limited Partner	Series A Preferred Equity	Series B Preferred Equity	USD ($)	USD ($)	Limited Partner	General Partner
					USD ($)	USD ($)	USD ($)			USD ($)	USD ($)
Unitholders equity, beginning balance at Dec. 31, 2013	$510,396	'	'	'	'	$0	$0	$0	'	$510,322	$74
Unitholders equity, beginning balance (in shares) at Dec. 31, 2013	'	'	'	'	'	0	0	0	'	57,280,000	'
Increase (Decrease) in Partners' Capital [Roll Forward]	'	'	'	'	'	'	'	'	'	'	'
Units issued to Legacy Board of Directors for services (in shares)	'	'	'	'	'	'	'	'	'	18,000	'
Units issued to Legacy Board of Directors for services	499	'	'	'	'	'	'	'	'	499	'
Stock issuance (in shares)	'	'	'	'	'	2,300,000	7,200,000	'	'	'	'
Proceeds from offering	'	'	'	'	'	55,192	174,261	'	'	'	'
Stock issuance	229,453	'	'	'	'	'	'	'	'	'	'
Unit-based compensation	2,620	'	'	'	'	'	'	'	'	2,620	'
Vesting of restricted and phantom units (in shares)	'	'	'	'	'	'	'	'	'	112,000	'
Offering costs associated with the issuance of units	-50	'	'	'	'	'	'	'	'	-50	'
Incentive Distribution Units issued in exchange for oil and natural gas properties (in shares)	'	'	'	'	'	'	'	100,000	'	'	'
Incentive Distribution Units issued in exchange for oil and natural gas properties	30,814	'	'	'	'	'	'	'	'	'	'
Distributions to preferred unitholders & Distributions to unitholders, $1.795 per unit	'	'	'	-6,944	-6,944	'	'	'	-103,681	-103,681	'
Net income	47,855	'	'	'	'	'	'	'	'	47,851	4
Unitholders equity, ending balance at Sep. 30, 2014	$710,962	'	'	'	'	$55,192	$174,261	$30,814	'	$450,617	$78
Unitholders equity, ending balance (in shares) at Sep. 30, 2014	'	'	'	'	'	2,300,000	7,200,000	100,000	'	57,410,000	'

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Unitholders Equity (Parenthetical) (Unitholders' Equity, Limited Partner, USD $)	9 Months Ended
	Sep. 30, 2014
Unitholders' Equity | Limited Partner	'
Distributions to unitholders (in dollars per share)	$1.80

Condensed_Consolidated_Stateme3

Condensed Consolidated Statement of Cash Flows (USD $)	9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Cash flows from operating activities:	'	'	'
Net income	$47,855	$11,627	'
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Depletion, depreciation, amortization and accretion	120,250	118,482	'
Amortization of debt discount and issuance costs	3,320	2,826	'
Impairment of long-lived assets	8,583	23,352	'
(Gain) loss on derivatives	-10,832	14,241	'
Equity in income of equity method investees	-309	-357	'
Distribution from equity method investee	1,302	631	'
Unit-based compensation	2,151	1,978	'
(Gain) loss on disposal of assets	-3,235	493	'
Changes in assets and liabilities:	'	'	'
Increase in accounts receivable, oil and natural gas	-20,258	-16,492	'
(Increase) decrease in accounts receivable, joint interest owners	-6,686	13,305	'
Decrease in accounts receivable, other	226	116	'
Increase in other assets	-695	-315	'
Increase (decrease) in accounts payable	-4,689	4,236	'
Increase in accrued oil and natural gas liabilities	24,980	23,020	'
Increase in other liabilities	12,644	4,989	'
Total adjustments	126,752	190,505	'
Net cash provided by operating activities	174,607	202,132	'
Cash flows from investing activities:	'	'	'
Investment in oil and natural gas properties	-594,344	-160,836	'
Increase in deposits on pending acquisitions	0	-902	'
Proceeds from sale of assets	5,334	-173	'
Investment in other equipment	-1,053	-2,046	'
Net cash settlements on commodity derivatives	-11,975	-4,666	'
Net cash used in investing activities	-602,038	-168,623	'
Cash flows from financing activities:	'	'	'
Proceeds from long-term debt	1,189,000	664,263	'
Payments of long-term debt	-870,000	-597,000	'
Payments of debt issuance costs	-9,933	-1,184	'
Proceeds from issuance of units, net	229,403	-10	'
Distributions to unitholders	-110,625	-99,022	'
Redemption of investment	0	-12	'
Net cash provided (used) by financing activities	427,845	-32,965	'
Net increase in cash and cash equivalents	414	544	'
Cash and cash equivalents, beginning of period	2,584	3,509	3,509
Cash and cash equivalents, end of period	2,998	4,053	2,584
Non-cash investing and financing activities:	'	'	'
Asset retirement obligations associated with properties sold	-4,804	9,853	-1,606
Asset retirement obligations associated with property acquisitions	50,487	1,590	'
Units issued in exchange for equity method investee	0	4,001	'
Note receivable received in exchange for the sale of oil and natural gas properties	0	11,857	'
Incentive distribution units issued in exchange for oil and natural gas properties	$30,814	$0	'

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Summary of Significant Accounting Policies	'
	Summary of Significant Accounting Policies
	(a)	Organization, Basis of Presentation and Description of Business
	Legacy Reserves LP ("LRLP," "Legacy" or the "Partnership") and, unless the context indicates otherwise, its affiliated entities, are referred to as Legacy in these financial statements.
	The accompanying condensed consolidated financial statements have been prepared on the accrual basis of accounting whereby revenues are recognized when earned, and expenses are recognized when incurred. These condensed consolidated financial statements as of September 30, 2014 and for the three and nine months ended September 30, 2014 and 2013 are unaudited. In the opinion of management, such financial statements include the adjustments and accruals, all of which are of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods. These interim results are not necessarily indicative of results for a full year.
	Certain information and footnote disclosures normally included in the financial statements prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) have been condensed or omitted in this Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). These condensed consolidated financial statements should be read in connection with the consolidated financial statements and notes thereto included in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2013.
	LRLP, a Delaware limited partnership, was formed by its general partner, Legacy Reserves GP, LLC (“LRGPLLC”), on October 26, 2005 to own and operate oil and natural gas properties. LRGPLLC is a Delaware limited liability company formed on October 26, 2005, and owns an approximate 0.03% general partner interest in LRLP.
	Significant information regarding rights of unitholders includes the following:
	•Right to receive, within 45 days after the end of each quarter, distributions of available cash, if distributions are declared.
	•No limited partner shall have any management power over LRLP’s business and affairs; the general partner shall conduct, direct and manage LRLP’s activities.
	•The general partner may be removed if such removal is approved by the unitholders holding at least 66 2/3 percent of the outstanding units, including units held by LRGPLLC and its affiliates, provided that a unit majority has elected a successor general partner.
	•Right to receive information reasonably required for tax reporting purposes within 90 days after the close of the calendar year.
	In the event of liquidation, after making required payments to Legacy's preferred unitholders, all property and cash in excess of that required to discharge all liabilities will be distributed to the unitholders and LRGPLLC in proportion to their capital account balances, as adjusted to reflect any gain or loss upon the sale or other disposition of Legacy’s assets in liquidation.
	Legacy owns and operates oil and natural gas producing properties located primarily in the Permian Basin (West Texas and Southeast New Mexico), Mid-Continent and Rocky Mountain regions of the United States.
	(b)	Accrued Oil and Natural Gas Liabilities
	Below are the components of accrued oil and natural gas liabilities as of September 30, 2014 and December 31, 2013:
		September 30,		December 31,
		2014		2013
		(In thousands)
	Revenue payable	$	29,037	$	21,686
	Accrued lease operating expense	20,755		11,914
	Accrued capital expenditures	14,069		10,409
	Accrued ad valorem tax	14,710		9,459
	Other	9,570		9,693
		$	88,141	$	63,161
	(c) Recent Accounting Pronouncements
	In April 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-08: Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity (ASU 2014-08). ASU 2014-08 changes the criteria for reporting discontinued operations while enhancing disclosures in this area and is effective for annual and interim periods beginning after December 15, 2014. Legacy is currently evaluating the provisions of ASU 2014-08 and assessing the impact, if any, it may have on its financial position and results of operations.
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (ASU 2014-09), which supersedes nearly all existing revenue recognition guidance under U.S. GAAP. The core principle of ASU 2014-09 is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration to which an entity expects to be entitled for those goods or services. ASU 2014-09 defines a five step process to achieve this core principle and, in doing so, more judgment and estimates may be required within the revenue recognition process than are required under existing U.S. GAAP. The standard is effective for annual periods beginning after December 15, 2016, and interim periods therein, using either of the following transition methods: (i) a full retrospective approach reflecting the application of the standard in each prior reporting period with the option to elect certain practical expedients, or (ii) a retrospective approach with the cumulative effect of initially adopting ASU 2014-09 recognized at the date of adoption (which includes additional footnote disclosures). Legacy is currently evaluating the impact of its pending adoption of ASU 2014-09 on its consolidated financial statements and has not yet determined the method by which it will adopt the standard in 2017.

LongTerm_Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Long-Term Debt	'
	Long-Term Debt
	Long-term debt consists of the following as of September 30, 2014 and December 31, 2013:
		September 30,			December 31,
		2014			2013
		(In thousands)
	Credit Facility due 2019	$	370,000		$	348,000
	8% Senior Notes due 2020	300,000			300,000
	6.625% Senior Notes due 2021	550,000			250,000
		1,220,000			898,000
	Unamortized discount on Senior Notes	(20,773		)	(19,307		)
	Total Long-Term Debt	$	1,199,227		$	878,693
	Credit Facility
	Previous Credit Agreement: On March 10, 2011, Legacy entered into a five-year $1 billion secured revolving credit facility (as amended, the "Previous Credit Agreement"). Borrowings under the Previous Credit Agreement were set to mature on March 10, 2016.
	Current Credit Agreement: On April 1, 2014, Legacy entered into a five-year $1.5 billion secured revolving credit facility with Wells Fargo Bank, National Association, as administrative agent, Compass Bank, as syndication agent, UBS Securities LLC and U.S. Bank National Association, as co-documentation agents and the lenders party thereto (the “Current Credit Agreement”). Borrowings under the Current Credit Agreement mature on April 1, 2019. Legacy's obligations under the Current Credit Agreement are secured by mortgages on over 80% of the total value of its oil and natural gas properties as well as a pledge of all of its ownership interests in its operating subsidiaries. The amount available for borrowing at any one time is limited to the borrowing base and contains a $2 million sub-limit for letters of credit. The borrowing base is currently set at $950 million. The borrowing base is subject to semi-annual redeterminations on April 1 and October 1 of each year. Additionally, either Legacy or the lenders may, once during each calendar year, elect to redetermine the borrowing base between scheduled redeterminations. Legacy also has the right, once during each calendar year, to request the redetermination of the borrowing base upon the proposed acquisition of certain oil and natural gas properties where the purchase price is greater than 10% of the borrowing base then in effect. Any increase in the borrowing base requires the consent of all the lenders and any decrease in or maintenance of the borrowing base must be approved by the lenders holding at least 66-2/3% of the outstanding aggregate principal amounts of the loans or participation interests in letters of credit issued under the Current Credit Agreement. If the requisite lenders do not agree on an increase or decrease, then the borrowing base will be the highest borrowing base acceptable to the lenders holding 66-2/3% of the outstanding aggregate principal amounts of the loans or participation interests in letters of credit issued under the Current Credit Agreement so long as it does not increase the borrowing base then in effect. Under the Current Credit Agreement, interest on debt outstanding is charged based on Legacy's selection of a one-, two-, three- or six-month LIBOR rate plus 1.50% to 2.50%, or the ABR which equals the highest of the prime rate, the Federal funds effective rate plus 0.50% or one-month LIBOR plus 1.00%, plus an applicable margin from 0.50% to 1.50% per annum, determined by the percentage of borrowing base then in effect that is drawn.
	The Current Credit Agreement contains various covenants that limit Legacy's ability to: (i) incur indebtedness, (ii) enter into certain leases, (iii) grant certain liens, (iv) enter into certain swaps, (v) make certain loans, acquisitions, capital expenditures and investments, (vi) make distributions other than from available cash, (vii) merge, consolidate or allow any material change in the character of its business and (viii) engage in certain asset dispositions, including a sale of all or substantially all of its assets. The Current Credit Agreement also contains covenants that, among other things, require Legacy to maintain specified ratios or conditions as follows: (i) total debt to EBITDA of not more than 4.5 to 1.0 through June 15, 2015 and 4.0 to 1.0 thereafter, (ii) consolidated current assets, including the unused amount of the total commitments, to consolidated current liabilities of not less than 1.0 to 1.0, excluding non-cash assets and liabilities under FASB Accounting Standards Codification 815, which includes the current portion of oil, natural gas and interest rate derivatives and (iii) specified minimum levels of natural gas hedges for each fiscal year. Unless otherwise noted, all material covenants under the Current Credit Agreement remain materially similar to the Previous Credit Agreement.
	As of September 30, 2014, Legacy had approximately $370 million drawn under the Current Credit Agreement at a weighted-average interest rate of 1.91%, leaving approximately $579.9 million of availability under the Current Credit Agreement. For the nine-month period ended September 30, 2014, Legacy paid in cash $7.1 million of interest expense on both the Previous and Current Credit Agreements.
	At September 30, 2014, Legacy was in compliance with all covenants of the Current Credit Agreement.
	8% Senior Notes Due 2020
	On December 4, 2012, Legacy and its 100% owned subsidiary Legacy Reserves Finance Corporation completed a private placement offering to eligible purchasers of an aggregate principal amount of $300 million of our 8% Senior Notes due 2020 (the "2020 Senior Notes"), which were subsequently registered through a public exchange offer that closed on January 8, 2014. The 2020 Senior Notes were issued at 97.848% of par.
	Legacy will have the option to redeem the 2020 Senior Notes, in whole or in part, at any time on or after December 1, 2016, at the specified redemption prices set forth below together with any accrued and unpaid interest, if any, to the date of redemption if redeemed during the twelve-month period beginning on December 1 of the years indicated below.
	Year	Percentage
	2016	104	%
	2017	102	%
	2018 and thereafter	100	%
	Prior to December 1, 2016, Legacy may redeem all or any part of the 2020 Senior Notes at the “make-whole” redemption price as defined in the indenture. In addition, prior to December 1, 2015, Legacy may at its option, redeem up to 35% of the aggregate principal amount of the 2020 Senior Notes at the redemption price of 108% with the net proceeds of a public or private equity offering. Legacy may be required to offer to repurchase the 2020 Senior Notes at a purchase price of 101% of the principal amount, plus accrued and unpaid interest, if any, to the redemption date, in the event of a change of control as defined by the indenture. Legacy's and Legacy Reserves Finance Corporation's obligations under the 2020 Senior Notes are guaranteed by its 100% owned subsidiaries Legacy Reserves Operating GP, LLC, Legacy Reserves Operating LP and Legacy Reserves Services, Inc., which constitute all of Legacy's wholly-owned subsidiaries other than Legacy Reserves Finance Corporation. In the future, the guarantees may be released or terminated under the following circumstances: (i) in connection with any sale or other disposition of all or substantially all of the properties of the guarantor; (ii) in connection with any sale or other disposition of sufficient capital stock of the guarantor so that it no longer qualifies as our Restricted Subsidiary (as defined in the indenture); (iii) if designated to be an unrestricted subsidiary; (iv) upon legal defeasance, covenant defeasance or satisfaction and discharge of the indenture; (v) upon the liquidation or dissolution of the guarantor provided no default or event of default has occurred or is occurring; (vi) at such time the guarantor does not have outstanding guarantees of its, or any other guarantor's, other, debt; or (vii) upon merging into, or transferring all of its properties to Legacy or another guarantor and ceasing to exist. Refer to Note 11 - Subsidiary Guarantors for further details on Legacy's guarantors.
	The indenture governing the 2020 Senior Notes limits Legacy's ability and the ability of certain of its subsidiaries to (i) sell assets; (ii) pay distributions on, repurchase or redeem equity interests or purchase or redeem Legacy's subordinated debt, provided that such subsidiaries may pay dividends to the holders of their equity interests (including Legacy) and Legacy may pay distributions to the holders of its equity interests subject to the absence of certain defaults, the satisfaction of a fixed charge coverage ratio test and so long as the amount of such distributions does not exceed the sum of available cash (as defined in the partnership agreement) at Legacy, net proceeds from the sales of certain securities and return of or reductions to capital from restricted investments; (iii) make certain investments; (iv) incur or guarantee additional indebtedness or issue preferred units; (v) create or incur certain liens; (vi) enter into agreements that restrict distributions or other payments from certain of its subsidiaries to Legacy; (vii) consolidate, merge or transfer all or substantially all of Legacy's assets; (viii) engage in certain transactions with affiliates; (ix) create unrestricted subsidiaries; and (x) engage in certain business activities. These covenants are subject to a number of important exceptions and qualifications. If at any time when the 2020 Senior Notes are rated investment grade by each of Moody's Investors Service, Inc. and Standard & Poor's Ratings Services and no Default (as defined in the indenture) has occurred and is continuing, many of such covenants will terminate and Legacy and its subsidiaries will cease to be subject to such covenants. The indenture also includes customary events of default. The Partnership is in compliance with all financial and other covenants of the 2020 Senior Notes.
	Interest is payable on June 1 and December 1 of each year.
	6.625% Senior Notes Due 2021
	On May 28, 2013, Legacy and its 100% owned subsidiary Legacy Reserves Finance Corporation completed a private placement offering to eligible purchasers of an aggregate principal amount of $250 million of our 6.625% Senior Notes due 2021 (the "2021 Senior Notes"), which were subsequently registered through a public exchange offer that closed on March 18, 2014. The 2021 Senior Notes were issued at 98.405% of par.
	On May 13, 2014, Legacy and its 100% owned subsidiary Legacy Reserves Finance Corporation completed a private placement offering to eligible purchasers of an aggregate principal amount of an additional $300 million of the 6.625% 2021 Senior Notes. These 2021 Senior Notes were issued at 99.0% of par.
	The terms of the 2021 Senior Notes, including details related to our guarantors, are substantially identical to the terms of the 2020 Senior Notes with the exception of the interest rate and redemption provisions noted below. Legacy will have the option to redeem the 2021 Senior Notes, in whole or in part, at any time on or after June 1, 2017, at the specified redemption prices set forth below together with any accrued and unpaid interest, if any, to the date of redemption if redeemed during the twelve-month period beginning on June 1 of the years indicated below.
	Year	Percentage
	2017	103.313	%
	2018	101.656	%
	2019 and thereafter	100	%
	Prior to June 1, 2017, Legacy may redeem all or any part of the 2021 Senior Notes at the “make-whole” redemption price as defined in the indenture. In addition, prior to June 1, 2016, Legacy may at its option, redeem up to 35% of the aggregate principal amount of the 2021 Senior Notes at the redemption price of 106.625% with the net proceeds of a public or private equity offering. Legacy may be required to offer to repurchase the 2021 Senior Notes at a purchase price of 101% of the principal amount, plus accrued and unpaid interest, if any, to the redemption date, in the event of a change of control as defined by the indenture. The Partnership is in compliance with all financial and other covenants of the 2021 Senior Notes.
	Interest is payable on June 1 and December 1 of each year.

Acquisitions_Acquisitions

Acquisitions Acquisitions	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions
	On June 4, 2014, Legacy purchased a non-operated interest in oil and natural gas properties located in the Piceance Basin in Garfield County, Colorado from WPX Energy Rocky Mountain, LLC , a subsidiary of WPX Energy, Inc., (the "WPX Acquisition") for a net purchase price of $360.0 million. Consideration included both cash and 300,000 Incentive Distribution Units representing limited partner interests in the Partnership (the "Incentive Distribution Units"), 100,000 of which vested immediately and the remainder of which are available to vest and also subject to forfeiture pursuant to the terms of a related Incentive Distribution Unitholder Agreement. This acquisition was accounted for as a business combination. The fully vested Incentive Distribution Units have been reflected in the financial statements at their estimated issuance date fair value of $30.8 million. No value was ascribed to the unvested Incentive Distribution Units upon the closing of the WPX Acquisition as the vesting of the unvested Incentive Distribution Units is dependent upon the consummation of future transactions with WPX and such Incentive Distribution Units will be a portion of the consideration of any such future transactions. During the nine month period ended September 30, 2014, Legacy incurred acquisition costs, recorded in general and administrative expense, of approximately $5.3 million related to the WPX Acquisition and other recent acquisitions.
	The allocation of the WPX Acquisition purchase price to the fair value of the acquired assets and liabilities assumed was as follows (in thousands):
	Proved oil and natural gas properties including related equipment	$	403,980
	Future abandonment costs	(43,989		)
	Fair value of net assets acquired	$	359,991
	Pro Forma Operating Results
	The following table reflects the unaudited pro forma results of operations as though the WPX Acquisition had occurred on January 1, 2013. The pro forma amounts are not necessarily indicative of the results that may be reported in the future and do not include any adjustments for acquisition related expenses.
			Three Months Ended September 30,			Nine Months Ended September 30,
			2013			2014		2013
	Revenues		$	150,664		$	450,069	$	410,362
	Net income (loss) attributable to unitholders		$	(6,846	)	$	46,993	$	4,263
	Income (loss) per unit — basic and diluted		$	(0.12	)	$	0.82	$	0.07
	Units used in computing income (loss) per unit:
	Basic		57,275			57,363		57,200
	Diluted		57,275			57,523		57,295
	The amounts of revenues and revenues in excess of direct operating expenses included in our consolidated statements of operations for the WPX Acquisition are shown in the table that follows. Direct operating expenses include lease operating expenses and production and other taxes.
			Three Months Ended September 30,			Nine Months Ended September 30,
			2014			2014
			(In thousands)
	Revenues		$	21,548		$	28,864
	Excess of revenues over direct operating expenses		$	10,372		$	14,924

Related_Party_Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2014
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Related Party Transactions
	Cary D. Brown, Chairman, President and Chief Executive Officer of LRGPLLC, Kyle A. McGraw, Director and Executive Vice President and Chief Development Officer of LRGPLLC and Dale Brown, Director of LRGPLLC, own interests in partnerships which, in turn, own a combined non-controlling 4.12% interest as limited partners in a partnership which owns the building that Legacy occupies. Monthly rent is $60,622, without respect to property taxes and insurance. The lease expires in September 2020.
	During the year ended December 31, 2012, Legacy acquired a 5% working interest in prospective Cline Shale acreage from FireWheel Energy, LLC ("FireWheel"), the operator of the properties, for $7.2 million. During the year ended December 31, 2013, Legacy acquired a 5% working interest in additional acreage from Firewheel for $1.2 million. FireWheel is a private-equity funded oil and natural gas exploration company in which Alan Brown, son of Dale Brown, a director of Legacy, and brother of Cary D. Brown, is a principal. The interests acquired by Legacy were marketed to numerous industry participants and are governed by an industry standard Participation Agreement and Joint Operating Agreement.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	From time to time Legacy is a party to various legal proceedings arising in the ordinary course of business. While the outcome of lawsuits cannot be predicted with certainty, Legacy is not currently a party to any proceeding that it believes could have a potential material adverse effect on its financial condition, results of operations or cash flows.
	Legacy is subject to numerous laws and regulations governing the discharge of materials into the environment or otherwise relating to environmental protection. To the extent laws are enacted or other governmental action is taken that restricts drilling or imposes environmental protection requirements that result in increased costs to the oil and natural gas industry in general, the business and prospects of Legacy could be adversely affected.
	Legacy has employment agreements with its officers that specify that if the officer is terminated by Legacy for other than cause or following a change in control, the officer shall receive severance pay ranging from 24 to 36 months salary plus bonus and COBRA benefits, respectively.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	As defined in FASB ASC 820-10, fair value is the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. ASC 820-10 requires disclosure that establishes a framework for measuring fair value and expands disclosure about fair value measurements. The statement requires fair value measurements be classified and disclosed in one of the following categories:
	Level 1:	Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities. Legacy considers active markets as those in which transactions for the assets or liabilities occur in sufficient frequency and volume to provide pricing information on an ongoing basis.
	Level 2:	Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. This category includes those derivative instruments that Legacy values using observable market data. Substantially all of these inputs are observable in the marketplace throughout the term of the derivative instrument, can be derived from observable data, or are supported by observable levels at which transactions are executed in the marketplace. Instruments in this category include non-exchange traded derivatives such as over-the-counter commodity price swaps and collars and interest rate swaps as well as long-term incentive plan liabilities calculated using the Black-Scholes model to estimate the fair value as of the measurement date.
	Level 3:	Measured based on prices or valuation models that require inputs that are both significant to the fair value measurement and less observable from objective sources (i.e. supported by little or no market activity). Legacy’s valuation models are primarily industry standard models that consider various inputs including: (a) quoted forward prices for commodities, (b) time value, and (c) current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Legacy does not currently have any instruments classified as Level 3.
	As required by ASC 820-10, financial assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurement. Legacy’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of the fair value of assets and liabilities and their placement within the fair value hierarchy levels.
	Fair Value on a Recurring Basis
	The following table sets forth by level within the fair value hierarchy Legacy’s financial assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2014:
			Fair Value Measurements at September 30, 2014 Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs			Significant Unobservable Inputs			Total Carrying Value as of
	Description		(Level 1)		(Level 2)			(Level 3)			September 30, 2014
			(In thousands)
	LTIP liability (a)		$	—	$	(1,249	)	$	—		$	(1,249	)
	Oil and natural gas commodity derivatives		—		38,322			—			38,322
	Interest rate swaps		—		(2,602		)	—			(2,602		)
	Total		$	—	$	34,471		$	—		$	34,471
	(a)	See Note 10 for further discussion on unit-based compensation expenses and the related Long-Term Incentive Plan ("LTIP") liability for certain grants accounted for under the liability method.
	Legacy estimates the fair values of the swaps based on published forward commodity price curves for the underlying commodities as of the date of the estimate for those commodities for which published forward pricing is readily available. For those commodity derivatives for which forward commodity price curves are not readily available, Legacy estimates, with the assistance of third-party pricing experts, the forward curves as of the date of the estimate. Legacy validates the data provided by third parties by understanding the pricing models used, obtaining market values from other pricing sources, analyzing pricing data in certain situations and confirming, where applicable, that those securities trade in active markets. Legacy estimates the option value of puts and calls combined into hedges, including three-way collars and enhanced swaps using an option pricing model which takes into account market volatility, market prices, contract parameters and discount rates based on published LIBOR rates and interest swap rates. In order to estimate the fair value of our interest rate swaps, Legacy uses a yield curve based on money market rates and interest rate swaps, extrapolates a forecast of future interest rates, estimates each future cash flow, derives discount factors to value the fixed and floating rate cash flows of each swap, and then discounts to present value all known (fixed) and forecasted (floating) swap cash flows. Curve building and discounting techniques used to establish the theoretical market value of interest bearing securities are based on readily available money market rates and interest swap market data. The determination of the fair values above incorporates various factors including the impact of our non-performance risk and the credit standing of the counterparties involved in the Partnership’s derivative contracts. The risk of nonperformance by the Partnership’s counterparties is mitigated by the fact that such current counterparties (or their affiliates) are also current or former bank lenders under the Partnership’s revolving credit facility. In addition, Legacy routinely monitors the creditworthiness of its counterparties. As the factors described above are based on significant assumptions made by management, these assumptions are the most sensitive to change.
	The following table sets forth a reconciliation of changes in the fair value of financial assets and liabilities classified as Level 3 in the fair value hierarchy:
			Significant Unobservable Inputs
			(Level 3)
			Three Months Ended					Nine Months Ended
			September 30,					September 30,
			2014		2013			2014			2013
			(In thousands)
	Beginning balance		$	—	$	32,386		$	20,615		$	29,966
	Transfers(a)		—					(14,552		)
	Total losses		—		(8,788		)	(6,740		)	(2,475		)
	Settlements, net		—		(523		)	677			(4,416		)
	Ending balance		$	—	$	23,075		$	—		$	23,075
	Losses included in earnings relating to derivatives still held as of September 30, 2014 and 2013		$	—	$	(9,311	)	$	—		$	(6,891	)
	(a)	As part of a routine review of accounting policies and practices, Legacy reviewed the assumptions and inputs used to value its derivative instruments and determined the material inputs (such as quoted market prices and oil and natural gas volatility) for its commodity derivatives more accurately correlate to the description of Level 2 instruments. As such, all instruments previously classified as Level 3 (oil and natural gas collars, swaptions and natural gas swaps for those derivatives indexed to the West Texas Waha, ANR-Oklahoma and CIG Indices) have been transferred to Level 2 instruments.
	During periods of market disruption, including periods of volatile oil and natural gas prices, rapid credit contraction or
	illiquidity, it may be difficult to value certain of the Partnership's derivative instruments if trading becomes less frequent and/or
	market data becomes less observable. There may be certain asset classes that were previously in active markets with observable data that become illiquid due to changes in the financial environment. In such cases, more derivative instruments may fall to Level 3 and thus require more subjectivity and management judgment. As such, valuations may include inputs and assumptions that are less observable or require greater estimation as well as valuation methods which are more sophisticated or require greater estimation thereby resulting in valuations with less certainty. Further, rapidly changing commodity and unprecedented credit and equity market conditions could materially impact the valuation of derivative instruments as reported within our consolidated financial statements and the period-to-period changes in value could vary significantly. Decreases in value may have a material adverse effect on our results of operations or financial condition
	Fair Value on a Non-Recurring Basis
	Nonfinancial assets and liabilities measured at fair value on a non-recurring basis include certain nonfinancial assets and liabilities as may be acquired in a business combination and thereby measured at fair value; measurements of oil and natural gas property impairments; and the initial recognition of asset retirement obligations ("ARO") for which fair value is used. These ARO estimates are derived from historical costs as well as management’s expectation of future cost environments. As there is no corroborating market activity to support the assumptions used, Legacy has designated these liabilities as Level 3. A reconciliation of the beginning and ending balances of Legacy’s asset retirement obligation is presented in Note 8.
	Assets measured at fair value during the nine-month period ended September 30, 2014 include:
			Fair Value Measurements at September 30, 2014 Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs			Significant Unobservable Inputs
	Description		(Level 1)		(Level 2)			(Level 3)
			(In thousands)
	Assets:
	Impairment (a)		$	—	$	—		$	7,828
	Acquisitions (b)		$	—	$	—		$	533,775
	(a)	Legacy reviews oil and natural gas properties for impairment when facts and circumstances indicate that their carrying value may not be recoverable. Legacy compares net capitalized costs of proved oil and natural gas properties to estimated undiscounted future net cash flows using management’s expectations of future oil and natural gas prices. These future price scenarios reflect Legacy’s estimation of future price volatility. During the nine-month period ended September 30, 2014, Legacy incurred impairment charges of $8.6 million as oil and natural gas properties with a net cost basis of $16.4 million were written down to their fair value of $7.8 million. In order to determine fair value, Legacy compares net capitalized costs of proved oil and natural gas properties to estimated undiscounted future net cash flows using management’s expectations of future oil and natural gas prices. These future price scenarios reflect Legacy’s estimation of future price volatility. If the net capitalized cost exceeds the undiscounted future net cash flows, Legacy writes the net cost basis down to the discounted future net cash flows, which is management's estimate of fair value. Significant inputs used to determine the fair value include estimates of: (i) reserves; (ii) future operating and development costs; (iii) future commodity prices; and (iv) a market-based weighted average cost of capital rate. The underlying commodity prices embedded in the Company's estimated cash flows are the product of a process that begins with NYMEX forward curve pricing, adjusted for estimated location and quality differentials, as well as other factors that Legacy's management believes will impact realizable prices. The inputs used by management for the fair value measurements utilized in this review include significant unobservable inputs, and therefore, the fair value measurements employed are classified as Level 3 for these types of assets.
	(b)	Assets and liabilities acquired in a business combination are recorded at fair value. During the nine-month period ended September 30, 2014, Legacy acquired oil and natural gas properties, inclusive of unproved acreage acquisitions, with a fair value of $533.8 million in the WPX Acquisition and 6 individually immaterial transactions. Properties acquired are recorded at fair value, which correlates to the discounted future net cash flow. Significant inputs used to determine the fair value include estimates of: (i) reserves; (ii) future operating and development costs; (iii) future commodity prices; and (iv) a market-based weighted average cost of capital rate. The underlying commodity prices embedded in the Company's estimated cash flows are the product of a process that begins with NYMEX forward curve pricing, adjusted for estimated location and quality differentials, as well as other factors that Legacy's management believes will impact realizable prices. For acquired unproved properties, the market-based weighted average cost of capital rate is subjected to additional project specific risking factors. The inputs used by management for the fair value measurements of these acquired oil and natural gas properties include significant unobservable inputs, and therefore, the fair value measurements employed are classified as Level 3 for these types of assets.
	The carrying amount of the revolving long-term debt of $370 million as of September 30, 2014 approximates fair value because Legacy's current borrowing rate does not materially differ from market rates for similar bank borrowings. Legacy has classified the revolving long-term debt as a Level 2 item within the fair value hierarchy. As of September 30, 2014, the fair values of the 2020 Senior Notes and the 2021 Senior Notes were $313.9 million and $536.6 million, respectively. As these valuations are based on unadjusted quoted prices in an active market, the fair values are classified as Level 1 items within the fair value hierarchy.
	During the nine-month period ended September 30, 2014, Legacy issued 100,000 Incentive Distribution Units to WPX Energy Rocky Mountains, LLC in conjunction with the WPX Acquisition. As these Incentive Distribution Units have no active market, Legacy utilized a Monte Carlo simulation to determine their fair value as of the date of issuance. Significant inputs used used in the Monte Carlo simulation included estimates of future distribution growth, unit price, acquisition activity and a market-based weighted average cost of capital rate. As these inputs are unobservable, their value related to the Incentive Distribution Units is classified as Level 3.

Derivative_Financial_Instrumen

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	Derivative Financial Instruments
	Commodity derivative transactions
	Due to the volatility of oil and natural gas prices, Legacy periodically enters into price-risk management transactions (e.g., swaps, enhanced swaps or collars) for a portion of its oil and natural gas production to achieve a more predictable cash flow, as well as to reduce exposure from price fluctuations. While the use of these arrangements limits Legacy’s ability to benefit from increases in the prices of oil and natural gas, it also reduces Legacy’s potential exposure to adverse price movements. Legacy’s arrangements, to the extent it enters into any, apply to only a portion of its production, provide only partial price protection against declines in oil and natural gas prices and limit Legacy’s potential gains from future increases in prices. None of these instruments are used for trading or speculative purposes and required no upfront or deferred cash premium paid or payable to our counterparty.
	All of these price risk management transactions are considered derivative instruments. These derivative instruments are intended to reduce Legacy’s price risk and may be considered hedges for economic purposes, but Legacy has chosen not to designate them as cash flow hedges for accounting purposes. Therefore, all derivative instruments are recorded on the balance sheet at fair value with changes in fair value being recorded in current period earnings.
	By using derivative instruments to mitigate exposures to changes in commodity prices, Legacy exposes itself to credit risk and market risk. Credit risk is the failure of the counterparty to perform under the terms of the derivative contract. When the fair value of a derivative contract is positive, the counterparty owes Legacy, which creates credit risk. Legacy minimizes the credit or repayment risk in derivative instruments by entering into transactions with high-quality counterparties, who currently are all current or former members of Legacy's lending group.
	The following table sets forth a reconciliation of the changes in fair value of Legacy's commodity derivatives for the three and nine months ended September 30, 2014 and 2013.
			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2014				2013				2014				2013
			(In thousands)
	Beginning fair value of commodity derivatives		$	(20,026	)		$	35,187			$	17,673			$	24,148
	Total gain (loss) - oil derivatives		43,279				(31,151		)		(2,751		)		(18,942		)
	Total gain - natural gas derivatives		12,715				727				11,426				844
	Crude oil derivative cash settlements paid		6,239				8,006				15,039				9,711
	Natural gas derivative cash settlements received		(3,885		)		(2,054		)		(3,065		)		(5,046		)
	Ending fair value of commodity derivatives		$	38,322			$	10,715			$	38,322			$	10,715
	Certain of our commodity derivatives and interest rate derivatives are presented on a net basis on the Consolidated Balance Sheets. The following table summarizes the gross fair values of our derivative instruments, presenting the impact of offsetting the derivative assets and liabilities on our Consolidated Balance Sheets as of the dates indicated below (in thousands):
			September 30, 2014
			Gross Amounts of Recognized Assets				Gross Amounts Offset in the Consolidated Balance Sheets				Net Amounts Presented in the Consolidated Balance Sheets
	Offsetting Derivative Assets:						(In thousands)
	Commodity derivatives		$	57,475			$	(19,038	)		$	38,437
	Total derivative assets		$	57,475			$	(19,038	)		$	38,437
	Offsetting Derivative Liabilities:
	Commodity derivatives		$	(19,153	)		$	19,038			$	(115	)
	Interest rate derivatives		(2,602		)		—				(2,602		)
	Total derivative liabilities		$	(21,755	)		$	19,038			$	(2,717	)
			December 31, 2013
			Gross Amounts of Recognized Assets				Gross Amounts Offset in the Consolidated Balance Sheets				Net Amounts Presented in the Consolidated Balance Sheets
	Offsetting Derivative Assets:						(In thousands)
	Commodity derivatives		$	46,356			$	(21,263	)		$	25,093
	Total derivative assets		$	46,356			$	(21,263	)		$	25,093
	Offsetting Derivative Liabilities:
	Commodity derivatives		$	(28,683	)		$	21,263			$	(7,420	)
	Interest rate derivatives		(4,759		)		—				(4,759		)
	Total derivative liabilities		$	(33,442	)		$	21,263			$	(12,179	)
	As of September 30, 2014, Legacy had the following NYMEX West Texas Intermediate ("WTI") crude oil swaps paying floating prices and receiving fixed prices for a portion of its future oil production as indicated below:
					Average
	Calendar Year		Volumes (Bbls)		Price per Bbl		Price Range per Bbl
	October-December 2014		792,451		$93.61		$87.50	-	$100.20
	2015		1,056,301		$93.93		$88.50	-	$100.20
	2016		228,600		$87.94		$86.30	-	$99.85
	2017		182,500		$84.75		$84.75
	As of September 30, 2014, Legacy had the following NYMEX WTI crude oil derivative three-way collar contracts that combine a long put, a short put and a short call as indicated below:
					Average Short		Average Long		Average Short
	Calendar Year		Volumes (Bbls)		Put Price per Bbl		Put Price per Bbl		Call Price per Bbl
	October-December 2014		202,400		$71.59		$96.59		$110.71
	2015		1,362,800		$65.08		$89.69		$111.84
	2016		621,300		$63.37		$88.37		$106.40
	2017		72,400		$60.00		$85.00		$104.20
	As of September 30, 2014, Legacy had the following NYMEX WTI crude oil enhanced swap contracts that combine a short put, a long put and a fixed-price swap as indicated below:
					Average Long		Average Short		Average
	Calendar Year		Volumes (Bbls)		Put Price per Bbl		Put Price per Bbl		Swap Price per Bbl
	2015		365,000		$60.00		$80.00		$92.35
	2016		183,000		$57.00		$82.00		$91.70
	2017		182,500		$57.00		$82.00		$90.85
	2018		127,750		$57.00		$82.00		$90.50
	As of September 30, 2014, Legacy had the following NYMEX WTI crude oil enhanced swap contracts that combine a short put and a fixed-price swap as indicated below:
					Average Short Put		Average Swap
	Calendar Year		Volumes (Bbls)		Price per Bbl		Price per Bbl
	2015		503,000		$74.12		$93.09
	As of September 30, 2014, Legacy had the following NYMEX West Texas Waha, ANR-OK and CIG-Rockies natural gas swaps paying floating natural gas prices and receiving fixed prices for a portion of its future natural gas production as indicated below:
					Average		Price
	Calendar Year		Volumes (MMBtu)		Price per MMBtu		Range per MMBtu
October-December 2014		6,280,331		$4.64		$3.61	-	$6.47
2015		16,219,300		$4.45		$4.15	-	$5.82
2016		1,419,200		$4.30		$4.12	-	$5.30
As of September 30, 2014, Legacy had the following NYMEX Henry Hub natural gas derivative three-way collar contracts that combine a long put, a short put and a short call as indicated below:
				Average Short Put		Average Long Put		Average Short Call
Calendar Year		Volumes (MMBtu)		Price per MMBtu		Price per MMBtu		Price per MMBtu
October-December 2014		120,000		$4.00		$4.65		$5.03
2015		8,040,000		$3.66		$4.21		$5.01
2016		5,580,000		$3.75		$4.25		$5.08
2017		5,040,000		$3.75		$4.25		$5.53
As of September 30, 2014, Legacy had the following Henry Hub NYMEX to Northwest Pipeline, NGPL Midcon, California SoCal NGI, San Juan Basin and West Texas WAHA natural gas differential swaps paying a floating differential and receiving a fixed differential for a portion of its future natural gas production as indicated below:
		October - December 2014				2015
				Average				Average
		Volumes (MMBtu)		Price per MMBtu		Volumes (MMBtu)		Price per MMBtu
NWPL		3,000,000		($0.09)		12,000,000		($0.13)
NGPL		240,000		($0.10)		480,000		($0.15)
SoCal		240,000		$0.29		240,000		$0.19
San Juan		240,000		($0.06)		480,000		($0.12)
WAHA		690,000		($0.06)		6,000,000		($0.10)
Interest rate derivative transactions
Due to the volatility of interest rates, Legacy periodically enters into interest rate risk management transactions in the form of interest rate swaps for a portion of its outstanding debt balance. These transactions allow Legacy to reduce exposure to interest rate fluctuations. While the use of these arrangements limits Legacy’s ability to benefit from decreases in interest rates, it also reduces Legacy’s potential exposure to increases in interest rates. Legacy’s arrangements, to the extent it enters into any, apply to only a portion of its outstanding debt balance, provide only partial protection against interest rate increases and limit Legacy’s potential savings from future interest rate declines. It is never management’s intention to hold or issue derivative instruments for speculative trading purposes. Conditions sometimes arise where actual borrowings are less than notional amounts hedged, which has, and could result in overhedged amounts.
Legacy accounts for these interest rate swaps at fair market value and included in the consolidated balance sheet as assets or liabilities.
Legacy does not designate these derivatives as cash flow hedges, even though they reduce its exposure to changes in interest rates. Therefore, the mark-to-market of these instruments is recorded in current earnings as a component of interest expense. The total impact on interest expense from the mark-to-market and settlements was as follows:
		Three Months Ended								Nine Months Ended
		September 30,								September 30,
		2014				2013				2014				2013
		(In thousands)
Beginning fair value of interest rate swaps		$	(3,332	)		$	(6,478	)		$	(4,759	)		$	(9,547	)
Total loss on interest rate swaps		(70		)		(648		)		(375		)		(929		)
Cash settlements paid		800				1,436				2,532				4,786
Ending fair value of interest rate swaps		$	(2,602	)		$	(5,690	)		$	(2,602	)		$	(5,690	)
The table below summarizes the interest rate swap position as of September 30, 2014:
											Estimated Fair Market Value at
Notional Amount				Fixed Rate			Effective Date		Maturity Date		September 30, 2014
(Dollars in thousands)
$	29,000			3.07	%		10/16/07		10/16/15		$	(793	)
$	13,000			3.112	%		11/16/07		11/16/15		(386		)
$	12,000			3.131	%		11/28/07		11/28/15		(357		)
$	50,000			2.5	%		10/10/08		10/10/15		(1,066		)
Total fair market value of interest rate derivatives											$	(2,602	)

Asset_Retirement_Obligation

Asset Retirement Obligation	9 Months Ended
	Sep. 30, 2014
Asset Retirement Obligation [Abstract]	'
Asset Retirement Obligation	'
	Asset Retirement Obligation
	AROs associated with the retirement of a tangible long-lived asset are recognized as a liability in the period in which it is incurred and becomes determinable. Under this method, when liabilities for dismantlement and abandonment costs, excluding salvage values, are initially recorded, the carrying amount of the related oil and natural gas properties is increased. The fair value of the ARO asset and liability is measured using expected future cash outflows discounted at Legacy’s credit-adjusted risk-free interest rate. Accretion of the liability is recognized each period using the interest method of allocation, and the capitalized cost is depleted over the useful life of the related asset.
	The following table reflects the changes in the ARO during the nine months ended September 30, 2014 and year ended December 31, 2013:
		September 30,			December 31,
		2014			2013
		(In thousands)
	Asset retirement obligation - beginning of period	$	175,786		$	162,183
	Liabilities incurred with properties acquired	50,487			10,969
	Liabilities incurred with properties drilled	—			494
	Liabilities settled during the period	(2,478		)	(2,441		)
	Liabilities associated with properties sold	(4,804		)	(1,606		)
	Current period accretion	5,698			6,187
	Asset retirement obligation - end of period	$	224,689		$	175,786

Partners_Equity

Partners' Equity	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Partners' Equity	'
	Partners' Equity
	Preferred Units
	On April 17, 2014, Legacy issued 2,000,000 of its 8% Series A Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (the "Series A Preferred Units") in a public offering at a price of $25.00 per unit. On May 12, 2014 Legacy issued an additional 300,000 Series A Preferred Units pursuant to the underwriters’ option to purchase additional Series A Preferred Units. Legacy received aggregate net proceeds of approximately $55.2 million, after deducting underwriting discounts and offering expenses, from the offering of Series A Preferred Units during the nine-months ended September 30, 2014.
	On June 17, 2014, Legacy issued 7,000,000 of its 8.00% Series B Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units (the "Series B Preferred Units") in a public offering at a price of $25.00 per unit. On July 1, 2014, the underwriters exercised their over-allotment option to purchase an additional 200,000 Series B Preferred Units. Legacy received aggregate net proceeds of approximately $174.3 million, after deducting underwriting discounts and offering expenses, from the offering of Series B Preferred Units during the nine-months ended September 30, 2014.
	Distributions on the Series A Preferred Units and Series B Preferred Units (collectively, the "Preferred Units") are cumulative from the date of original issue and will be payable monthly in arrears on the 15th day of each month of each year, when, as and if declared by the board of directors of the Partnership's general partner. Distributions on the Series A Preferred Units will be payable from, and including, the date of the original issuance to, but not including April 15, 2024 at an initial rate of 8.00% per annum of the stated liquidation preference. Distributions on the Series B Preferred Units will be payable from, and including, the date of the original issuance to, but not including June 15, 2024 at an initial rate of 8.00% per annum of the stated liquidation preference. Distributions accruing on and after April 15, 2024 for the Series A Preferred Units and June 15, 2024 for the Series B Preferred Units will accrue at an annual rate equal to the sum of (a) three-month LIBOR as calculated on each applicable date of determination and (b) 5.24% for Series A and 5.26% for Series B, based on the $25.00 liquidation preference per preferred unit.
	At any time on or after April 15, 2019 or June 15, 2019, Legacy may redeem the Series A Preferred Units or Series B Preferred Units, respectively, in whole or in part at a redemption price of $25.00 per Preferred Unit plus an amount equal to all accumulated and unpaid distributions thereon through and including the date of redemption, whether or not declared. Legacy may also redeem the Preferred Units in the event of a Change of Control.
	The Series A Preferred Units and the Series B Preferred Units trade on NASDAQ under the symbols "LGCYP" and "LGCYO,” respectively.
	Incentive Distribution Units
	On June 4, 2014, Legacy issued 300,000 Incentive Distribution Units to WPX Energy Rocky Mountain, LLC (“WPX”) as part of the WPX Acquisition. The Incentive Distribution Units issued to WPX include 100,000 Incentive Distribution Units that immediately vested along with the ability to vest in up to an additional 200,000 Incentive Distribution Units (the “Unvested IDUs”) in connection with any future asset sales or transactions completed with Legacy. Incentive Distribution Units that are not issued to WPX or other parties will remain in Legacy's treasury for the benefit of all limited partners until such time as Legacy may make future issuances of Incentive Distribution Units.
	The Incentive Distribution Units represent a right to incremental cash distributions from Legacy after certain target levels of distributions are paid to unitholders, which targets are set above the current levels of Legacy's distributions to unitholders. The Unvested IDUs do not participate in cash distributions from Legacy until vested. The Unvested IDUs will automatically be forfeited on each of the first two anniversaries of the closing date of the WPX Acquisition in an amount per forfeiture equal to 66,666 Incentive Distribution Units and on the third anniversary of the closing date of the WPX Acquisition in an amount equal to 66,668 Incentive Distribution Units. Unvested IDUs that have not been forfeited will vest ratably at a rate of 10,000 Incentive Distribution Units per $35.5 million of additional cash consideration that is paid by Legacy to WPX or to a third party (along with the fair market value of any non-cash consideration) in connection with the consummation of any transaction by which Legacy acquires oil and natural gas properties (or rights therein or other assets related thereto) from WPX or jointly with WPX.
	In addition, the vested and outstanding Incentive Distribution Units held by WPX may be converted by Legacy, subject to applicable conversion factors, into units on a one-for-one basis at any time when Legacy has made a distribution in respect of its units for each of the four full fiscal quarters prior to the delivery of its conversion notice, and the amount of the distribution in respect of the units for the full quarter immediately preceding delivery of its conversion notice was equal to at least $0.90 per unit; and the amount of all distributions during each quarter within the four-quarter period immediately preceding delivery of its conversion notice did not exceed the adjusted operating surplus for such quarter. Further, WPX also has the ability to similarly convert any of its vested Incentive Distribution Units beginning three years after June 4, 2014. WPX may not transfer any of the Incentive Distribution Units it holds to any person that is not a controlled affiliate of WPX.
	Income (loss) per unit
	The following table sets forth the computation of basic and diluted income (loss) per unit:
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2014		2013			2014		2013
		(In thousands)
	Income (loss) available to unitholders	$	59,066	$	(3,422	)	$	40,911	$	11,627
	Weighted average number of units outstanding	57,406		57,275			57,363		57,200
	Effect of dilutive securities:
	Restricted and phantom units	237		—			160		95
	Weighted average units and potential units outstanding	57,643		57,275			57,523		57,295
	Basic income (loss) per unit	$	1.03	$	(0.06	)	$	0.71	$	0.2
	Diluted income (loss) per unit	$	1.02	$	(0.06	)	$	0.71	$	0.2
	For the three months ended September 30, 2014, 151,189 restricted units and 191,305 phantom units were excluded from the calculation of diluted income per unit due to their anti-dilutive effect. For the nine months ended September 30, 2014, 185,396 restricted units and 234,589 phantom units were excluded from the calculation of diluted income per unit due to their anti-dilutive effect. For the three and nine months ended September 30, 2013, 425,195 and 330,116 restricted and phantom units were excluded from the calculation of diluted income per unit due to their anti-dilutive effect.

UnitBased_Compensation

Unit-Based Compensation	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Unit-Based Compensation	'
	Unit-Based Compensation
	Long-Term Incentive Plan
	On March 15, 2006, the LTIP for Legacy was implemented for its employees, consultants and directors, its affiliates and its general partner. The awards under the LTIP may include unit grants, restricted units, phantom units, unit options and unit appreciation rights ("UARs"). The LTIP permits the grant of awards that may be made or settled in units up to an aggregate of 2,000,000 units. As of September 30, 2014, grants of awards net of forfeitures and, in the case of phantom units, historical exercises covering 1,254,655 units had been made, comprised of 266,014 unit option awards, 534,298 restricted unit awards, 323,965 phantom unit awards and 130,378 unit awards. The UAR awards granted under the LTIP may only be settled in cash, and therefore are not included in the aggregate number of units granted under the LTIP. The LTIP is administered by the compensation committee (the “Compensation Committee”) of the board of directors of LRGPLLC.
	The cost of employee services in exchange for an award of equity instruments is measured based on a grant-date fair value of the award (with limited exceptions), and that cost must generally be recognized over the vesting period of the award. However, if an entity that nominally has the choice of settling awards by issuing stock predominately settles in cash, or if an entity usually settles in cash whenever an employee asks for cash settlement, the entity is settling a substantive liability rather than repurchasing an equity instrument. Due to Legacy’s historical practice of settling options, UARs and certain phantom unit awards in cash, Legacy accounted for unit options, UARs and certain phantom unit awards by utilizing the liability method. The liability method requires companies to measure the cost of the employee services in exchange for a cash award based on the fair value of the underlying security at the end of each reporting period. Compensation cost is recognized based on the change in the liability between periods. However, during 2013, the Compensation Committee revised the executive compensation policy and amended certain historical phantom unit award agreements to eliminate the Compensation Committee's option of settling phantom unit awards for executive officers in cash. Due to the elimination of the cash settlement option, Legacy now accounts for executive phantom unit awards under the equity method as described in ASC 718. Legacy treated the amendment as a cancellation of the historical awards and a grant of new awards in the period, though the award amounts and vesting terms remained unchanged.
	Unit Appreciation Rights and Unit Options
	A UAR is a notional unit that entitles the holder, upon vesting, to receive cash valued at the difference between the closing price of units on the exercise date and the exercise price, as determined on the date of grant. Because these awards are settled in cash, Legacy is accounting for the UARs by utilizing the liability method.
	During the year ended December 31, 2013, Legacy issued 156,650 UARs to employees which vest ratably over a three-year period and 77,506 UARs to employees which vest at the end of a three-year period. During the nine-month period ended September 30, 2014, Legacy issued 111,600 UARs to employees which vest ratably over a three-year period and 105,174 UARs to employees which vest at the end of a three-year period. All UARs granted in 2013 and 2014 expire seven years from the grant date and are exercisable when they vest.
	For the nine-month periods ended September 30, 2014 and 2013, Legacy recorded $(23.7) thousand and $0.7 million, respectively, of compensation expense (benefit) due to the change in liability from December 31, 2013 and 2012, respectively, based on its use of the Black-Scholes model to estimate the September 30, 2014 and 2013 fair value of these UARs (see Note 6). As of September 30, 2014, there was a total of approximately $1.6 million of unrecognized compensation costs related to the unexercised and non-vested portion of these UARs. At September 30, 2014, this cost was expected to be recognized over a weighted-average period of approximately 2.38 years. Compensation expense is based upon the fair value as of September 30, 2014 and is recognized as a percentage of the service period satisfied. Based on historical data, Legacy has assumed a volatility factor of approximately 35% and employed the Black-Scholes model to estimate the September 30, 2014 fair value to be realized as compensation cost based on the percentage of service period satisfied. Based on historical data, Legacy has assumed an estimated forfeiture rate of 4.6%. Legacy will adjust the estimated forfeiture rate based upon actual experience. Legacy has assumed an annual distribution rate of $2.44 per unit.
	A summary of UAR and unit option activity for the nine months ended September 30, 2014 is as follows:
			Units		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term	Aggregate Intrinsic Value
	Outstanding at January 1, 2014		627,043		$	25.99
	Granted		216,774		28.85
	Exercised		(136,585	)	24.34
	Forfeited		(39,168	)	27.13
	Outstanding at September 30, 2014		668,064		$	27.19	5.4	$	1,723,770
	Options and UARs exercisable at September 30, 2014		200,089		$	25.27	3.6	$	910,458
	The following table summarizes the status of Legacy’s non-vested UARs since January 1, 2014:
			Non-Vested UARs
			Number of Units		Weighted-Average Exercise Price
	Non-vested at January 1, 2014		386,755		$	27.21
	Granted		216,774		28.85
	Vested		(97,386	)	26.89
	Forfeited		(38,168	)	27.58
	Non-vested at September 30, 2014		467,975		$	28.01
	Legacy has used a weighted-average risk-free interest rate of 1.8% in its Black-Scholes calculation of fair value, which approximates the U.S. Treasury interest rates at September 30, 2014 whose terms are consistent with the expected life of the UARs and unit options. Expected life represents the period of time that UARs and unit options are expected to be outstanding and is based on Legacy’s best estimate. The following table represents the weighted-average assumptions used for the Black-Scholes option-pricing model.
		Nine Months Ended
		September 30,
		2014
	Expected life (years)	5.36
	Risk free interest rate	1.8	%
	Annual distribution rate per unit	$2.44
	Volatility	35	%
	Phantom Units
	Legacy has also issued phantom units under the LTIP to both executive officers, as described below, and certain other employees. A phantom unit is a notional unit that entitles the holder, upon vesting, to receive, in the case of non-executive employees, cash valued at the closing price of units on the vesting date, or, at the discretion of the Compensation Committee, the same number of Partnership units. Because Legacy’s current intent is to settle these non-executive phantom unit awards in cash, Legacy is accounting for these phantom units by utilizing the liability method. As mentioned above, in the case of executive employees, the Compensation Committee revised the historical grants for all executive phantom units to eliminate any election for cash payment. As these awards can now only be settled in Partnership units, Legacy is accounting for these phantom units by utilizing the equity method.
	On September 21, 2009, the board of directors of LRGPLLC, upon the recommendation of the Compensation Committee, implemented an equity-based incentive compensation policy applicable to the executive officers of Legacy. In addition to cash bonus awards, under the compensation plan, the executives are eligible for both subjective and objective grants of phantom units. The subjective, or service-based, grants may be awarded up to a maximum percentage of annual salary as determined by the Compensation Committee. Once granted, these phantom units vest ratably over a three-year period. The objective, or performance-based, grants may be awarded up to a maximum percentage of annual salary as determined by the Compensation Committee. However, the amount to vest each year for the three-year vesting period will be determined on each vesting date based on a three-step process, with the first two steps each comprising 50% of the total vesting amount while the third step is the sum of the first two steps. The first step in the process will be a function of Total Unitholder Return (“TUR”) for the Partnership and the percentage rank of the Legacy TUR among a peer group of upstream master limited partnerships, as determined by the Compensation Committee at the beginning of each year. In the second step, the Legacy TUR will be compared to the TUR of a group of master limited partnerships included in the Alerian MLP Index. The third step is the addition of the above two steps to determine the total performance-based awards to vest. On March 7, 2013, the board of directors of LRGPLLC, upon the recommendation of the Compensation Committee, approved a revised compensation policy (the “Revised Policy.”) This Revised Policy applies to incentive awards granted after the fiscal year ended 2013. While the Revised Policy measures TUR against both the peer group and Alerian MLP Index, the measurement periods were increased to a three-year cumulative measurement period with a corresponding increase in vesting from a ratable three-year vesting to three-year cliff vesting. Performance based phantom units subject to vesting which do not vest in a given year will be forfeited. With respect to both the subjective and objective units awarded under both compensation policies, distribution equivalent rights ("DERs") will accumulate and accrue based on the total number of actual amounts vested and will be payable at the date of vesting. However, due to the aforementioned revision for executive employees, accrued DERs paid at the date of vesting will be treated as distributions in the period paid rather than being recognized as compensation expense over the life of the award.
	On March 7, 2013, the Compensation Committee approved the award of 46,430 subjective, or service-based, phantom units and 76,723 objective, or performance based, phantom units to Legacy’s executive officers. On March 4, 2014, the Compensation Committee approved the award of 117,197 subjective, or service-based, phantom units and 102,572 objective, or performance based, phantom units to Legacy’s executive officers.
	Compensation expense (benefit) related to the phantom units and associated DERs was $1.6 million and $0.7 million for the nine months ended September 30, 2014 and 2013, respectively.
	Restricted Units
	During the year ended December 31, 2013, Legacy issued an aggregate of 85,728 restricted units to non-executive employees. These restricted units awarded mostly vest ratably over a three-year period all beginning on or around the date of grant. During the nine-month period ended September 30, 2014, Legacy issued an aggregate of 108,415 restricted units to non-executive employees. These restricted units awarded vest ratably over a three-year period. Compensation expense related to restricted units was $1.7 million and $1.7 million for the nine months ended September 30, 2014 and 2013, respectively. As of September 30, 2014, there was a total of $5.5 million of unrecognized compensation expense related to the unvested portion of these restricted units. At September 30, 2014, this cost was expected to be recognized over a weighted-average period of 2.4 years. Pursuant to the provisions of ASC 718, Legacy’s issued units, as reflected in the accompanying consolidated balance sheet at September 30, 2014, do not include 256,031 units related to unvested restricted unit awards.
	Board Units
	On May 14, 2013, Legacy granted and issued 3,715 units to each of its five non-employee directors. The value of each unit was $27.39 at the time of issuance. On May 15, 2014, Legacy granted and issued 3,628 units to each of its five non-employee directors. The value of each unit was $27.50 at the time of issuance.

Subsidiary_Guarantors

Subsidiary Guarantors	9 Months Ended
	Sep. 30, 2014
Guarantees [Abstract]	'
Subsidiary Guarantors	'
	Subsidiary Guarantors
	On April 2, 2014, we filed a registration statement on Form S-3 with the Securities and Exchange Commission ("SEC") to register the issuance and sale of, among other securities, our debt securities, which may be co-issued by Legacy Reserves Finance Corporation. The registration statement also registered guarantees of debt securities by Legacy Reserves Operating GP, LLC, Legacy Reserves Operating LP and Legacy Reserves Services, Inc. The Partnership's 2020 Senior Notes were issued in a private offering on December 4, 2012 and were subsequently registered through a public exchange offer that closed on January 8, 2014. The Partnership's 2021 Senior Notes were issued in two separate private offerings on May 28, 2013 and May 8, 2014. $250 million aggregate principal amount of our 2021 Senior Notes were subsequently registered through a public exchange offer that closed on March 18, 2014. The 2020 Senior Notes and the 2021 Senior Notes are guaranteed by our 100% owned subsidiaries Legacy Reserves Operating GP, LLC, Legacy Reserves Operating LP and Legacy Reserves Services, Inc., which constitute all of our wholly-owned subsidiaries other than Legacy Reserves Finance Corporation, and certain other future subsidiaries (the “Guarantors”, together with any future 100% owned subsidiaries that guarantee the Partnership's 2020 Senior Notes and 2021 Senior Notes, the “Subsidiaries”). The Subsidiaries are 100% owned by the Partnership and the guarantees by the Subsidiaries are full and unconditional, except for customary release provisions described in Note 2 - Long-Term Debt. The Partnership has no assets or operations independent of the Subsidiaries, and there are no significant restrictions upon the ability of the Subsidiaries to distribute funds to the Partnership. The guarantees constitute joint and several obligations of the Guarantors.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	On October 1, 2014, the lenders under Legacy's Current Credit Agreement redetermined and reaffirmed its borrowing base under Legacy's revolving credit facility at $950 million. The next redetermination of the borrowing base is scheduled for April 1, 2015.
	On October 8, 2014, Legacy issued 11,500,000 units, including 1,500,000 units purchased pursuant to the underwriters' option to purchase additional units, at an offering price of $26.43 per unit, net of underwriting discounts and commissions, generating total net proceeds of approximately $303.9 million after deducting underwriting discounts and commissions but before offering expenses. The proceeds from the offering will be used for general partnership purposes, including funding future acquisitions or repaying a portion of the borrowings outstanding under Legacy's revolving credit facility. Amounts repaid under Legacy's revolving credit facility may be reborrowed, subject to the terms of the facility.
	On October 20, 2014, Legacy’s board of directors approved a distribution of $0.61 per unit payable on November 14, 2014 to unitholders of record on October 31, 2014.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of Accounting	'
	The accompanying condensed consolidated financial statements have been prepared on the accrual basis of accounting whereby revenues are recognized when earned, and expenses are recognized when incurred. These condensed consolidated financial statements as of September 30, 2014 and for the three and nine months ended September 30, 2014 and 2013 are unaudited. In the opinion of management, such financial statements include the adjustments and accruals, all of which are of a normal recurring nature, which are necessary for a fair presentation of the results for the interim periods. These interim results are not necessarily indicative of results for a full year.
	Certain information and footnote disclosures normally included in the financial statements prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) have been condensed or omitted in this Form 10-Q pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). These condensed consolidated financial statements should be read in connection with the consolidated financial statements and notes thereto included in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2013.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In April 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-08: Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity (ASU 2014-08). ASU 2014-08 changes the criteria for reporting discontinued operations while enhancing disclosures in this area and is effective for annual and interim periods beginning after December 15, 2014. Legacy is currently evaluating the provisions of ASU 2014-08 and assessing the impact, if any, it may have on its financial position and results of operations.
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (ASU 2014-09), which supersedes nearly all existing revenue recognition guidance under U.S. GAAP. The core principle of ASU 2014-09 is to recognize revenues when promised goods or services are transferred to customers in an amount that reflects the consideration to which an entity expects to be entitled for those goods or services. ASU 2014-09 defines a five step process to achieve this core principle and, in doing so, more judgment and estimates may be required within the revenue recognition process than are required under existing U.S. GAAP. The standard is effective for annual periods beginning after December 15, 2016, and interim periods therein, using either of the following transition methods: (i) a full retrospective approach reflecting the application of the standard in each prior reporting period with the option to elect certain practical expedients, or (ii) a retrospective approach with the cumulative effect of initially adopting ASU 2014-09 recognized at the date of adoption (which includes additional footnote disclosures). Legacy is currently evaluating the impact of its pending adoption of ASU 2014-09 on its consolidated financial statements and has not yet determined the method by which it will adopt the standard in 2017.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Schedule of components of accrued oil and natural gas liabilities	'
	Below are the components of accrued oil and natural gas liabilities as of September 30, 2014 and December 31, 2013:
		September 30,		December 31,
		2014		2013
		(In thousands)
	Revenue payable	$	29,037	$	21,686
	Accrued lease operating expense	20,755		11,914
	Accrued capital expenditures	14,069		10,409
	Accrued ad valorem tax	14,710		9,459
	Other	9,570		9,693
		$	88,141	$	63,161

LongTerm_Debt_Tables

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Schedule of long-term debt	'
	Long-term debt consists of the following as of September 30, 2014 and December 31, 2013:
		September 30,			December 31,
		2014			2013
		(In thousands)
	Credit Facility due 2019	$	370,000		$	348,000
	8% Senior Notes due 2020	300,000			300,000
	6.625% Senior Notes due 2021	550,000			250,000
		1,220,000			898,000
	Unamortized discount on Senior Notes	(20,773		)	(19,307		)
	Total Long-Term Debt	$	1,199,227		$	878,693
Schedule of debt redemption	'
	Legacy will have the option to redeem the 2020 Senior Notes, in whole or in part, at any time on or after December 1, 2016, at the specified redemption prices set forth below together with any accrued and unpaid interest, if any, to the date of redemption if redeemed during the twelve-month period beginning on December 1 of the years indicated below.
	Year	Percentage
	2016	104	%
	2017	102	%
	2018 and thereafter	100	%
	Legacy will have the option to redeem the 2021 Senior Notes, in whole or in part, at any time on or after June 1, 2017, at the specified redemption prices set forth below together with any accrued and unpaid interest, if any, to the date of redemption if redeemed during the twelve-month period beginning on June 1 of the years indicated below.
	Year	Percentage
	2017	103.313	%
	2018	101.656	%
	2019 and thereafter	100	%

Acquisitions_Tables

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2014
Business Combinations [Abstract]	'
Schedule of allocation of the purchase price to the fair value of the acquired assets and liabilities assumed	'
	The allocation of the WPX Acquisition purchase price to the fair value of the acquired assets and liabilities assumed was as follows (in thousands):
	Proved oil and natural gas properties including related equipment	$	403,980
	Future abandonment costs	(43,989		)
	Fair value of net assets acquired	$	359,991
Schedule of unaudited pro forma results of operations	'
	The following table reflects the unaudited pro forma results of operations as though the WPX Acquisition had occurred on January 1, 2013. The pro forma amounts are not necessarily indicative of the results that may be reported in the future and do not include any adjustments for acquisition related expenses.
			Three Months Ended September 30,			Nine Months Ended September 30,
			2013			2014		2013
	Revenues		$	150,664		$	450,069	$	410,362
	Net income (loss) attributable to unitholders		$	(6,846	)	$	46,993	$	4,263
	Income (loss) per unit — basic and diluted		$	(0.12	)	$	0.82	$	0.07
	Units used in computing income (loss) per unit:
	Basic		57,275			57,363		57,200
	Diluted		57,275			57,523		57,295
	The amounts of revenues and revenues in excess of direct operating expenses included in our consolidated statements of operations for the WPX Acquisition are shown in the table that follows. Direct operating expenses include lease operating expenses and production and other taxes.
			Three Months Ended September 30,			Nine Months Ended September 30,
			2014			2014
			(In thousands)
	Revenues		$	21,548		$	28,864
	Excess of revenues over direct operating expenses		$	10,372		$	14,924

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Schedule of financial assets and liabilities that were accounted for at fair value on a recurring basis	'
	The following table sets forth by level within the fair value hierarchy Legacy’s financial assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2014:
			Fair Value Measurements at September 30, 2014 Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs			Significant Unobservable Inputs			Total Carrying Value as of
	Description		(Level 1)		(Level 2)			(Level 3)			September 30, 2014
			(In thousands)
	LTIP liability (a)		$	—	$	(1,249	)	$	—		$	(1,249	)
	Oil and natural gas commodity derivatives		—		38,322			—			38,322
	Interest rate swaps		—		(2,602		)	—			(2,602		)
	Total		$	—	$	34,471		$	—		$	34,471
	(a)	See Note 10 for further discussion on unit-based compensation expenses and the related Long-Term Incentive Plan ("LTIP") liability for certain grants accounted for under the liability method.
Reconciliation of changes in the fair value of financial assets and liabilities classified as Level 3	'
	The following table sets forth a reconciliation of changes in the fair value of financial assets and liabilities classified as Level 3 in the fair value hierarchy:
			Significant Unobservable Inputs
			(Level 3)
			Three Months Ended					Nine Months Ended
			September 30,					September 30,
			2014		2013			2014			2013
			(In thousands)
	Beginning balance		$	—	$	32,386		$	20,615		$	29,966
	Transfers(a)		—					(14,552		)
	Total losses		—		(8,788		)	(6,740		)	(2,475		)
	Settlements, net		—		(523		)	677			(4,416		)
	Ending balance		$	—	$	23,075		$	—		$	23,075
	Losses included in earnings relating to derivatives still held as of September 30, 2014 and 2013		$	—	$	(9,311	)	$	—		$	(6,891	)
	(a)	As part of a routine review of accounting policies and practices, Legacy reviewed the assumptions and inputs used to value its derivative instruments and determined the material inputs (such as quoted market prices and oil and natural gas volatility) for its commodity derivatives more accurately correlate to the description of Level 2 instruments. As such, all instruments previously classified as Level 3 (oil and natural gas collars, swaptions and natural gas swaps for those derivatives indexed to the West Texas Waha, ANR-Oklahoma and CIG Indices) have been transferred to Level 2 instruments.
Schedule of fair value measurements of proved oil and natural gas properties	'
	Assets measured at fair value during the nine-month period ended September 30, 2014 include:
			Fair Value Measurements at September 30, 2014 Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs			Significant Unobservable Inputs
	Description		(Level 1)		(Level 2)			(Level 3)
			(In thousands)
	Assets:
	Impairment (a)		$	—	$	—		$	7,828
	Acquisitions (b)		$	—	$	—		$	533,775
	(a)	Legacy reviews oil and natural gas properties for impairment when facts and circumstances indicate that their carrying value may not be recoverable. Legacy compares net capitalized costs of proved oil and natural gas properties to estimated undiscounted future net cash flows using management’s expectations of future oil and natural gas prices. These future price scenarios reflect Legacy’s estimation of future price volatility. During the nine-month period ended September 30, 2014, Legacy incurred impairment charges of $8.6 million as oil and natural gas properties with a net cost basis of $16.4 million were written down to their fair value of $7.8 million. In order to determine fair value, Legacy compares net capitalized costs of proved oil and natural gas properties to estimated undiscounted future net cash flows using management’s expectations of future oil and natural gas prices. These future price scenarios reflect Legacy’s estimation of future price volatility. If the net capitalized cost exceeds the undiscounted future net cash flows, Legacy writes the net cost basis down to the discounted future net cash flows, which is management's estimate of fair value. Significant inputs used to determine the fair value include estimates of: (i) reserves; (ii) future operating and development costs; (iii) future commodity prices; and (iv) a market-based weighted average cost of capital rate. The underlying commodity prices embedded in the Company's estimated cash flows are the product of a process that begins with NYMEX forward curve pricing, adjusted for estimated location and quality differentials, as well as other factors that Legacy's management believes will impact realizable prices. The inputs used by management for the fair value measurements utilized in this review include significant unobservable inputs, and therefore, the fair value measurements employed are classified as Level 3 for these types of assets.
	(b)	Assets and liabilities acquired in a business combination are recorded at fair value. During the nine-month period ended September 30, 2014, Legacy acquired oil and natural gas properties, inclusive of unproved acreage acquisitions, with a fair value of $533.8 million in the WPX Acquisition and 6 individually immaterial transactions. Properties acquired are recorded at fair value, which correlates to the discounted future net cash flow. Significant inputs used to determine the fair value include estimates of: (i) reserves; (ii) future operating and development costs; (iii) future commodity prices; and (iv) a market-based weighted average cost of capital rate. The underlying commodity prices embedded in the Company's estimated cash flows are the product of a process that begins with NYMEX forward curve pricing, adjusted for estimated location and quality differentials, as well as other factors that Legacy's management believes will impact realizable prices. For acquired unproved properties, the market-based weighted average cost of capital rate is subjected to additional project specific risking factors. The inputs used by management for the fair value measurements of these acquired oil and natural gas properties include significant unobservable inputs, and therefore, the fair value measurements employed are classified as Level 3 for these types of assets.

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Schedule of reconciliation of the changes in fair value of Legacy's commodity derivatives	'
	The following table sets forth a reconciliation of the changes in fair value of Legacy's commodity derivatives for the three and nine months ended September 30, 2014 and 2013.
			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2014				2013				2014				2013
			(In thousands)
	Beginning fair value of commodity derivatives		$	(20,026	)		$	35,187			$	17,673			$	24,148
	Total gain (loss) - oil derivatives		43,279				(31,151		)		(2,751		)		(18,942		)
	Total gain - natural gas derivatives		12,715				727				11,426				844
	Crude oil derivative cash settlements paid		6,239				8,006				15,039				9,711
	Natural gas derivative cash settlements received		(3,885		)		(2,054		)		(3,065		)		(5,046		)
	Ending fair value of commodity derivatives		$	38,322			$	10,715			$	38,322			$	10,715
Schedule of gross fair values of our derivative instruments, presenting the impact of offsetting the derivative assets and liabilities	'
	The following table summarizes the gross fair values of our derivative instruments, presenting the impact of offsetting the derivative assets and liabilities on our Consolidated Balance Sheets as of the dates indicated below (in thousands):
			September 30, 2014
			Gross Amounts of Recognized Assets				Gross Amounts Offset in the Consolidated Balance Sheets				Net Amounts Presented in the Consolidated Balance Sheets
	Offsetting Derivative Assets:						(In thousands)
	Commodity derivatives		$	57,475			$	(19,038	)		$	38,437
	Total derivative assets		$	57,475			$	(19,038	)		$	38,437
	Offsetting Derivative Liabilities:
	Commodity derivatives		$	(19,153	)		$	19,038			$	(115	)
	Interest rate derivatives		(2,602		)		—				(2,602		)
	Total derivative liabilities		$	(21,755	)		$	19,038			$	(2,717	)
			December 31, 2013
			Gross Amounts of Recognized Assets				Gross Amounts Offset in the Consolidated Balance Sheets				Net Amounts Presented in the Consolidated Balance Sheets
	Offsetting Derivative Assets:						(In thousands)
	Commodity derivatives		$	46,356			$	(21,263	)		$	25,093
	Total derivative assets		$	46,356			$	(21,263	)		$	25,093
	Offsetting Derivative Liabilities:
	Commodity derivatives		$	(28,683	)		$	21,263			$	(7,420	)
	Interest rate derivatives		(4,759		)		—				(4,759		)
	Total derivative liabilities		$	(33,442	)		$	21,263			$	(12,179	)
Schedule of notional amounts of outstanding derivative positions	'
	As of September 30, 2014, Legacy had the following NYMEX West Texas Intermediate ("WTI") crude oil swaps paying floating prices and receiving fixed prices for a portion of its future oil production as indicated below:
					Average
	Calendar Year		Volumes (Bbls)		Price per Bbl		Price Range per Bbl
	October-December 2014		792,451		$93.61		$87.50	-	$100.20
	2015		1,056,301		$93.93		$88.50	-	$100.20
	2016		228,600		$87.94		$86.30	-	$99.85
	2017		182,500		$84.75		$84.75
	As of September 30, 2014, Legacy had the following NYMEX WTI crude oil derivative three-way collar contracts that combine a long put, a short put and a short call as indicated below:
					Average Short		Average Long		Average Short
	Calendar Year		Volumes (Bbls)		Put Price per Bbl		Put Price per Bbl		Call Price per Bbl
	October-December 2014		202,400		$71.59		$96.59		$110.71
	2015		1,362,800		$65.08		$89.69		$111.84
	2016		621,300		$63.37		$88.37		$106.40
	2017		72,400		$60.00		$85.00		$104.20
	As of September 30, 2014, Legacy had the following NYMEX WTI crude oil enhanced swap contracts that combine a short put, a long put and a fixed-price swap as indicated below:
					Average Long		Average Short		Average
	Calendar Year		Volumes (Bbls)		Put Price per Bbl		Put Price per Bbl		Swap Price per Bbl
	2015		365,000		$60.00		$80.00		$92.35
	2016		183,000		$57.00		$82.00		$91.70
	2017		182,500		$57.00		$82.00		$90.85
	2018		127,750		$57.00		$82.00		$90.50
	As of September 30, 2014, Legacy had the following NYMEX WTI crude oil enhanced swap contracts that combine a short put and a fixed-price swap as indicated below:
					Average Short Put		Average Swap
	Calendar Year		Volumes (Bbls)		Price per Bbl		Price per Bbl
	2015		503,000		$74.12		$93.09
	As of September 30, 2014, Legacy had the following NYMEX West Texas Waha, ANR-OK and CIG-Rockies natural gas swaps paying floating natural gas prices and receiving fixed prices for a portion of its future natural gas production as indicated below:
					Average		Price
	Calendar Year		Volumes (MMBtu)		Price per MMBtu		Range per MMBtu
	October-December 2014		6,280,331		$4.64		$3.61	-	$6.47
	2015		16,219,300		$4.45		$4.15	-	$5.82
	2016		1,419,200		$4.30		$4.12	-	$5.30
	As of September 30, 2014, Legacy had the following NYMEX Henry Hub natural gas derivative three-way collar contracts that combine a long put, a short put and a short call as indicated below:
					Average Short Put		Average Long Put		Average Short Call
	Calendar Year		Volumes (MMBtu)		Price per MMBtu		Price per MMBtu		Price per MMBtu
	October-December 2014		120,000		$4.00		$4.65		$5.03
	2015		8,040,000		$3.66		$4.21		$5.01
	2016		5,580,000		$3.75		$4.25		$5.08
	2017		5,040,000		$3.75		$4.25		$5.53
	As of September 30, 2014, Legacy had the following Henry Hub NYMEX to Northwest Pipeline, NGPL Midcon, California SoCal NGI, San Juan Basin and West Texas WAHA natural gas differential swaps paying a floating differential and receiving a fixed differential for a portion of its future natural gas production as indicated below:
			October - December 2014				2015
					Average				Average
			Volumes (MMBtu)		Price per MMBtu		Volumes (MMBtu)		Price per MMBtu
	NWPL		3,000,000		($0.09)		12,000,000		($0.13)
	NGPL		240,000		($0.10)		480,000		($0.15)
	SoCal		240,000		$0.29		240,000		$0.19
	San Juan		240,000		($0.06)		480,000		($0.12)
	WAHA		690,000		($0.06)		6,000,000		($0.10)
Schedule of total impact on interest expense from the mark-to-market and settlements	'
	The total impact on interest expense from the mark-to-market and settlements was as follows:
			Three Months Ended								Nine Months Ended
			September 30,								September 30,
			2014				2013				2014				2013
			(In thousands)
	Beginning fair value of interest rate swaps		$	(3,332	)		$	(6,478	)		$	(4,759	)		$	(9,547	)
	Total loss on interest rate swaps		(70		)		(648		)		(375		)		(929		)
	Cash settlements paid		800				1,436				2,532				4,786
	Ending fair value of interest rate swaps		$	(2,602	)		$	(5,690	)		$	(2,602	)		$	(5,690	)
Schedule of interest rate swap liabilities	'
	The table below summarizes the interest rate swap position as of September 30, 2014:
												Estimated Fair Market Value at
	Notional Amount				Fixed Rate			Effective Date		Maturity Date		September 30, 2014
	(Dollars in thousands)
	$	29,000			3.07	%		10/16/07		10/16/15		$	(793	)
	$	13,000			3.112	%		11/16/07		11/16/15		(386		)
	$	12,000			3.131	%		11/28/07		11/28/15		(357		)
	$	50,000			2.5	%		10/10/08		10/10/15		(1,066		)
	Total fair market value of interest rate derivatives											$	(2,602	)

Asset_Retirement_Obligation_Ta

Asset Retirement Obligation (Tables)	9 Months Ended
	Sep. 30, 2014
Asset Retirement Obligation [Abstract]	'
Schedule of changes in asset retirement obligations	'
	The following table reflects the changes in the ARO during the nine months ended September 30, 2014 and year ended December 31, 2013:
		September 30,			December 31,
		2014			2013
		(In thousands)
	Asset retirement obligation - beginning of period	$	175,786		$	162,183
	Liabilities incurred with properties acquired	50,487			10,969
	Liabilities incurred with properties drilled	—			494
	Liabilities settled during the period	(2,478		)	(2,441		)
	Liabilities associated with properties sold	(4,804		)	(1,606		)
	Current period accretion	5,698			6,187
	Asset retirement obligation - end of period	$	224,689		$	175,786

Partners_Equity_Tables

Partners' Equity (Tables)	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Schedule of computation of basic and diluted income (loss) per unit	'
	The following table sets forth the computation of basic and diluted income (loss) per unit:
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2014		2013			2014		2013
		(In thousands)
	Income (loss) available to unitholders	$	59,066	$	(3,422	)	$	40,911	$	11,627
	Weighted average number of units outstanding	57,406		57,275			57,363		57,200
	Effect of dilutive securities:
	Restricted and phantom units	237		—			160		95
	Weighted average units and potential units outstanding	57,643		57,275			57,523		57,295
	Basic income (loss) per unit	$	1.03	$	(0.06	)	$	0.71	$	0.2
	Diluted income (loss) per unit	$	1.02	$	(0.06	)	$	0.71	$	0.2

UnitBased_Compensation_Tables

Unit-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Schedule of option and UAR activity	'
	A summary of UAR and unit option activity for the nine months ended September 30, 2014 is as follows:
			Units		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term	Aggregate Intrinsic Value
	Outstanding at January 1, 2014		627,043		$	25.99
	Granted		216,774		28.85
	Exercised		(136,585	)	24.34
	Forfeited		(39,168	)	27.13
	Outstanding at September 30, 2014		668,064		$	27.19	5.4	$	1,723,770
	Options and UARs exercisable at September 30, 2014		200,089		$	25.27	3.6	$	910,458
Schedule of status of the Partnershipbs non-vested UARs	'
	The following table summarizes the status of Legacy’s non-vested UARs since January 1, 2014:
			Non-Vested UARs
			Number of Units		Weighted-Average Exercise Price
	Non-vested at January 1, 2014		386,755		$	27.21
	Granted		216,774		28.85
	Vested		(97,386	)	26.89
	Forfeited		(38,168	)	27.58
	Non-vested at September 30, 2014		467,975		$	28.01
Schedule of weighted average assumptions used for the Black-Scholes option-pricing model	'
	The following table represents the weighted-average assumptions used for the Black-Scholes option-pricing model.
		Nine Months Ended
		September 30,
		2014
	Expected life (years)	5.36
	Risk free interest rate	1.8	%
	Annual distribution rate per unit	$2.44
	Volatility	35	%

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Other Narrative (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'	'
General partner's equity, percent	0.03%	0.03%
Term of right to receive distributions of available cash after quarter end	'45 days	'
Minimum percentage of unitholder approval to remove general partner	66.67%	'
Term of right to receive information reasonably required for tax reporting purposes after close of year	'90 days	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Accrued Oil and Natural Gas Liabilities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'	'
Revenue payable	$29,037	$21,686
Accrued lease operating expense	20,755	11,914
Accrued capital expenditures	14,069	10,409
Accrued ad valorem tax	14,710	9,459
Other	9,570	9,693
Accrued oil and natural gas liabilities	$88,141	$63,161

LongTerm_Debt_Schedule_of_Long

Long-Term Debt - Schedule of Long-term Debt (Details) (USD $)	Sep. 30, 2014	13-May-14	Dec. 31, 2013	28-May-13
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'	'	'	'
Long-term debt, gross	$1,220,000	'	$898,000	'
Unamortized discount on Senior Notes	-20,773	'	-19,307	'
Total Long-Term Debt	1,199,227	'	878,693	'
Senior notes | 8% Senior Notes due 2020	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'
Stated interest rate	8.00%	'	'	'
Long-term debt, gross	300,000	'	300,000	'
Senior notes | 6.625% Senior Notes due 2021	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'
Stated interest rate	6.63%	'	'	'
Long-term debt, gross	550,000	300,000	250,000	250,000
Credit facility due 2019	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'
Long-term debt, gross	$370,000	'	$348,000	'

LongTerm_Debt_Credit_Facility_

Long-Term Debt - Credit Facility (Details) (USD $)	0 Months Ended	9 Months Ended
	Mar. 10, 2011	Sep. 30, 2014	Apr. 02, 2014	Dec. 31, 2013
Line of Credit Facility [Line Items]	'	'	'	'
Long-term debt, gross	'	$1,220,000,000	'	$898,000,000
Credit Facility due 2016	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Expiration period	'5 years	'	'	'
Maximum borrowing capacity	1,000,000,000	'	'	'
Credit facility due 2019	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Expiration period	'5 years	'	'	'
Maximum borrowing capacity	'	'	1,500,000,000	'
Minimum percent of total value securing credit agreement	'	'	80.00%	'
Current borrowing capacity	'	'	950,000,000	'
Purchase price of properties as a percentage of borrowing base required for potential re-determination of borrowing base, minimum	'	'	10.00%	'
Minimum percent of outstanding principal amount required for changes to credit agreement	'	'	66.67%	'
Long-term debt, gross	'	370,000,000	'	348,000,000
Interest rate at period end	'	1.91%	'	'
Remaining borrowing capacity	'	579,900,000	'	'
Interest Paid	'	7,100,000	'	'
Credit facility due 2019 | Maximum	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Ratio of indebtedness to EBITDA	'	4.5	'	'
Credit facility due 2019 | Minimum	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Ratio of indebtedness to EBITDA	'	4	'	'
Letter of Credit [Member]	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Maximum borrowing capacity	'	'	$2,000,000	'
one-, two-, three- or six-month LIBOR [Member] | Credit facility due 2019 | Maximum	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Basis spread on variable rate	2.50%	'	'	'
one-, two-, three- or six-month LIBOR [Member] | Credit facility due 2019 | Minimum	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Basis spread on variable rate	1.50%	'	'	'
Alternate Base Rate, Federal Funds [Member] | Credit facility due 2019	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Basis spread on variable rate	0.50%	'	'	'
Alternate Base Rate, one-month LIBOR [Member] | Credit facility due 2019	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Basis spread on variable rate	1.00%	'	'	'
Standard Alternate Base Rate [Member] | Credit facility due 2019 | Maximum	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Basis spread on variable rate	1.50%	'	'	'
Standard Alternate Base Rate [Member] | Credit facility due 2019 | Minimum	'	'	'	'
Line of Credit Facility [Line Items]	'	'	'	'
Basis spread on variable rate	0.50%	'	'	'

LongTerm_Debt_Senior_Notes_Det

Long-Term Debt - Senior Notes (Details) (USD $)

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Dec. 04, 2012

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

13-May-14

Dec. 31, 2013

28-May-13

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

13-May-14

28-May-13

Dec. 04, 2012

In Thousands, unless otherwise specified

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Legacy Reserves Finance Corporation

Legacy Reserves Finance Corporation

Legacy Reserves Finance Corporation

8% Senior Notes due 2020

8% Senior Notes due 2020

8% Senior Notes due 2020

8% Senior Notes due 2020

8% Senior Notes due 2020

8% Senior Notes due 2020

8% Senior Notes due 2020

8% Senior Notes due 2020

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

Company Option [Member]

Change in Control [Member]

2016

2017

2018 and thereafter

Company Option [Member]

Change in Control [Member]

2017

2018

2019 and thereafter

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stated interest rate

'

'

8.00%

'

'

'

'

'

'

'

6.63%

'

'

'

'

'

'

'

'

'

'

'

Ownership interest

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

100.00%

100.00%

Long-term debt, gross

$1,220,000

$898,000

$300,000

$300,000

'

'

'

'

'

'

$550,000

$300,000

$250,000

$250,000

'

'

'

'

'

'

'

'

Issuance percent of par

'

'

'

'

97.85%

'

'

'

'

'

'

99.00%

'

98.41%

'

'

'

'

'

'

'

'

Redemption price percentage

'

'

'

'

'

108.00%

101.00%

104.00%

102.00%

100.00%

'

'

'

'

106.63%

101.00%

103.31%

101.66%

100.00%

'

'

'

Percent of notes eligible of early redemption

'

'

'

35.00%

'

'

'

'

'

'

35.00%

'

'

'

'

'

'

'

'

'

'

'

Acquisitions_Details

Acquisitions (Details) (USD $)	3 Months Ended	9 Months Ended	0 Months Ended		3 Months Ended	9 Months Ended			9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Jun. 04, 2014	Jun. 04, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jun. 04, 2014	Sep. 30, 2014
			Incentive Distribution Equity	WPX acquisition	WPX acquisition	WPX acquisition	WPX acquisition	WPX acquisition	WPX acquisition
									Immediate vesting
Business Acquisition [Line Items]	'	'	'	'	'	'	'	'	'
Acquisition purchase price	'	'	'	$360,000,000	'	'	'	'	'
Equity interests issuable (in shares)	'	'	'	300,000	'	'	'	'	100,000
Incentive Distribution Units issued in exchange for oil and natural gas properties	'	30,814,000	30,814,000	'	'	'	'	'	'
Business Acquisition, Transaction Costs	'	'	'	'	'	5,300,000	'	'	'
Schedule of allocation of the purchase price to the fair value of the acquired assets and liabilities assumed	'	'	'	'	'	'	'	'	'
Proved oil and natural gas properties including related equipment	'	'	'	'	'	'	'	403,980,000	'
Future abandonment costs	'	'	'	'	'	'	'	-43,989,000	'
Fair value of net assets acquired	'	'	'	'	'	'	'	359,991,000	'
Pro Forma Operating Results	'	'	'	'	'	'	'	'	'
Revenues	'	'	'	'	150,664,000	450,069,000	410,362,000	'	'
Net income (loss) attributable to unitholders	'	'	'	'	-6,846,000	46,993,000	4,263,000	'	'
Income (loss) per unit - basic and diluted (in dollars per share)	'	'	'	'	($0.12)	$0.82	$0.07	'	'
Basic (in shares)	'	'	'	'	57,275,000	57,363,000	57,200,000	'	'
Diluted (in shares)	'	'	'	'	57,275,000	57,523,000	57,295,000	'	'
Revenues	21,548,000	28,864,000	'	'	'	'	'	'	'
Excess of revenues over direct operating expenses	$10,372,000	$14,924,000	'	'	'	'	'	'	'

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2012
	President/CEO and Director, EVP, CDO	FireWheel Energy, LLC	FireWheel Energy, LLC
Related Party Transaction [Line Items]	'	'	'
Noncontrolling ownership interest in third party by related party	4.12%	'	'
Monthly rent expense	$60,622	'	'
Working interest associated with prospective acreage	'	5.00%	5.00%
Prospective acreage purchase price	'	$1,200,000	$7,200,000

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (Officer)	9 Months Ended
	Sep. 30, 2014
Officer	'
Loss Contingencies [Line Items]	'
Employment agreements with officers, severance pay consideration period, minimum	'24 months
Employment agreements with officers, severance pay consideration period, maximum	'36 months

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)

9 Months Ended

0 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

Sep. 30, 2014

Dec. 31, 2013

Jun. 04, 2014

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

13-May-14

Dec. 31, 2013

28-May-13

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

WPX acquisition

WPX acquisition

Credit facility due 2019

Credit facility due 2019

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Senior notes

Quoted Prices in Active Markets for Identical Assets (Level 1)

Quoted Prices in Active Markets for Identical Assets (Level 1)

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Recurring

Nonrecurring

Nonrecurring

Nonrecurring

Immediate vesting

8% Senior Notes due 2020

8% Senior Notes due 2020

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

6.625% Senior Notes due 2021

Senior notes

Senior notes

Commodity derivatives

Interest rate swaps

Quoted Prices in Active Markets for Identical Assets (Level 1)

Quoted Prices in Active Markets for Identical Assets (Level 1)

Quoted Prices in Active Markets for Identical Assets (Level 1)

Significant Other Observable Inputs (Level 2)

Significant Other Observable Inputs (Level 2)

Significant Other Observable Inputs (Level 2)

Significant Unobservable Inputs (Level 3)

Significant Unobservable Inputs (Level 3)

Significant Unobservable Inputs (Level 3)

Significant Unobservable Inputs (Level 3)

Significant Unobservable Inputs (Level 3)

Significant Unobservable Inputs (Level 3)

Significant Unobservable Inputs (Level 3)

Significant Unobservable Inputs (Level 3)

Quoted Prices in Active Markets for Identical Assets (Level 1)

Significant Other Observable Inputs (Level 2)

Significant Unobservable Inputs (Level 3)

8% Senior Notes due 2020

6.625% Senior Notes due 2021

Oil and natural gas

Commodity derivatives

Interest rate swaps

Commodity derivatives

Interest rate swaps

Derivative assets

Derivative assets

Commodity derivatives

Interest rate swaps

transaction

Oil and natural gas

Oil and natural gas

Oil and natural gas

Schedule of financial assets and liabilities that were accounted for at fair value on a recurring basis

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

LTIP liability

'

'

'

'

'

'

'

'

'

'

'

'

'

'

($1,249,000)

'

'

$0

'

'

($1,249,000)

'

'

$0

'

$0

'

'

'

'

'

'

'

'

Derivative asset

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

38,322,000

'

'

0

'

'

38,322,000

'

'

'

'

'

'

'

0

'

'

'

'

Derivative liability

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-2,602,000

'

'

0

'

'

-2,602,000

'

'

'

'

'

'

'

0

'

'

'

Fair value of assets (liabilities)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

34,471,000

'

'

0

'

'

34,471,000

'

'

0

'

0

'

'

'

'

'

'

'

'

Reconciliation of changes in the fair value of financial assets and liabilities classified as Level 3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Beginning balance

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

32,386,000

20,615,000

29,966,000

'

'

'

'

'

'

'

Transfers

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

-14,552,000

'

'

'

'

'

'

'

'

Total losses

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

-8,788,000

-6,740,000

-2,475,000

'

'

'

'

'

'

'

Settlements, net

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

-523,000

677,000

-4,416,000

'

'

'

'

'

'

'

Ending balance

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

23,075,000

0

23,075,000

'

'

'

'

'

'

'

Losses included in earnings relating to derivatives still held as of September 30, 2014 and 2013

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

-6,891,000

0

-9,311,000

'

'

'

'

'

Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Abstract]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Impairment

2,085,528,000

1,535,429,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

0

7,828,000

Acquisitions

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

0

533,775,000

Impairment of long-lived assets

8,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Oil and gas properties, gross

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

16,400,000

Number of immaterial transactions

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6

Long-term debt, gross

1,220,000,000

898,000,000

'

'

370,000,000

348,000,000

300,000,000

300,000,000

550,000,000

300,000,000

250,000,000

250,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of notes payable

'

'

'

'

'

'

'

'

'

'

'

'

$313,900,000

$536,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity interests issuable (in shares)

'

'

300,000

100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Commodity Derivatives (Details) (USD $)

9 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

In Thousands, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Dec. 31, 2012

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Not designated as hedging instrument

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Commodity contract

Oil

Oil

Oil

Oil

Natural gas

Natural gas

Natural gas

Natural gas

Realized and Unrealized Gains (Losses) Related to Derivatives [Roll Forward]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Beginning fair value of interest rate swaps

'

'

$38,322

($20,026)

$17,673

$10,715

$35,187

$24,148

'

'

'

'

'

'

'

'

Total gain (loss) on derivatives

10,832

-14,241

'

'

'

'

'

'

43,279

-31,151

-2,751

-18,942

12,715

727

11,426

844

Derivative cash settlements paid (received)

11,975

4,666

'

'

'

'

'

'

6,239

8,006

15,039

9,711

-3,885

-2,054

-3,065

-5,046

Ending fair value of interest rate swaps

'

'

$38,322

($20,026)

$17,673

$10,715

$35,187

$24,148

'

'

'

'

'

'

'

'

Derivative_Financial_Instrumen3

Derivative Financial Instruments - Offsetting Derivative Assets and Liabilities (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Offsetting Derivative Assets:	'	'
Gross Amounts of Recognized Assets	$57,475	$46,356
Gross Amounts Offset in the Consolidated Balance Sheets	-19,038	-21,263
Net Amounts Presented in the Consolidated Balance Sheets	38,437	25,093
Offsetting Derivative Liabilities:	'	'
Gross Amounts of Recognized Liabilities	-21,755	-33,442
Gross Amounts Offset in the Consolidated Balance Sheets	19,038	21,263
Net Amounts Presented in the Consolidated Balance Sheets	-2,717	-12,179
Commodity contract	'	'
Offsetting Derivative Assets:	'	'
Gross Amounts of Recognized Assets	57,475	46,356
Gross Amounts Offset in the Consolidated Balance Sheets	-19,038	-21,263
Net Amounts Presented in the Consolidated Balance Sheets	38,437	25,093
Offsetting Derivative Liabilities:	'	'
Gross Amounts of Recognized Liabilities	-19,153	-28,683
Gross Amounts Offset in the Consolidated Balance Sheets	19,038	21,263
Net Amounts Presented in the Consolidated Balance Sheets	-115	-7,420
Interest rate contract	'	'
Offsetting Derivative Liabilities:	'	'
Gross Amounts of Recognized Liabilities	-2,602	-4,759
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts Presented in the Consolidated Balance Sheets	($2,602)	($4,759)

Derivative_Financial_Instrumen4

Derivative Financial Instruments - Schedule of Derivatives, Notional Amounts Outstanding (Details) (USD $)	Sep. 30, 2014
In Thousands, unless otherwise specified	bbl
NYMEX WTI Swaps | Crude Oil | October-December 2014	'
Derivative [Line Items]	'
Volumes	792,451
Average Price	93.61
NYMEX WTI Swaps | Crude Oil | October-December 2014 | Minimum	'
Derivative [Line Items]	'
Price Range	87.5
NYMEX WTI Swaps | Crude Oil | October-December 2014 | Maximum	'
Derivative [Line Items]	'
Price Range	100.2
NYMEX WTI Swaps | Crude Oil | 2015	'
Derivative [Line Items]	'
Volumes	1,056,301
Average Price	93.93
NYMEX WTI Swaps | Crude Oil | 2015 | Minimum	'
Derivative [Line Items]	'
Price Range	88.5
NYMEX WTI Swaps | Crude Oil | 2015 | Maximum	'
Derivative [Line Items]	'
Price Range	100.2
NYMEX WTI Swaps | Crude Oil | 2016	'
Derivative [Line Items]	'
Volumes	228,600
Average Price	87.94
NYMEX WTI Swaps | Crude Oil | 2016 | Minimum	'
Derivative [Line Items]	'
Price Range	86.3
NYMEX WTI Swaps | Crude Oil | 2016 | Maximum	'
Derivative [Line Items]	'
Price Range	99.85
NYMEX WTI Swaps | Crude Oil | 2017	'
Derivative [Line Items]	'
Volumes	182,500
Average Price	84.75
Price Range	84.75
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | October-December 2014	'
Derivative [Line Items]	'
Volumes	202,400
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | October-December 2014 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	71.59
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | October-December 2014 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	96.59
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | October-December 2014 | Call option | Short	'
Derivative [Line Items]	'
Average Strike Price	110.71
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2015	'
Derivative [Line Items]	'
Volumes	1,362,800
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2015 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	65.08
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2015 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	89.69
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2015 | Call option | Short	'
Derivative [Line Items]	'
Average Strike Price	111.84
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2016	'
Derivative [Line Items]	'
Volumes	621,300
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2016 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	63.37
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2016 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	88.37
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2016 | Call option | Short	'
Derivative [Line Items]	'
Average Strike Price	106.4
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2017	'
Derivative [Line Items]	'
Volumes	72,400
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2017 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	60
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2017 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	85
NYMEX WTI Derivative Three-Way Collar Contracts | Crude Oil | 2017 | Call option | Short	'
Derivative [Line Items]	'
Average Strike Price	104.2
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2015	'
Derivative [Line Items]	'
Volumes	365,000
Average Price	92.35
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2015 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	80
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2015 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	60
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2016	'
Derivative [Line Items]	'
Volumes	183,000
Average Price	91.7
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2016 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	82
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2016 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	57
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2017	'
Derivative [Line Items]	'
Volumes	182,500
Average Price	90.85
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2017 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	82
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2017 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	57
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2018	'
Derivative [Line Items]	'
Volumes	127,750
Average Price	90.5
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2018 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	82
NYMEX WTI Enhanced Swap Contracts 1 | Crude Oil | 2018 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	57
NYMEX WTI Enhanced Swap Contracts 2 | Crude Oil | 2015	'
Derivative [Line Items]	'
Volumes	503,000
Average Price	93.09
NYMEX WTI Enhanced Swap Contracts 2 | Crude Oil | 2015 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	74.12
NYMEX Henry Hub, Waha, ANR-OK and CIG-Rockies Swaps | Natural gas | October-December 2014	'
Derivative [Line Items]	'
Volumes	6,280,331
Average Price	4.64
NYMEX Henry Hub, Waha, ANR-OK and CIG-Rockies Swaps | Natural gas | October-December 2014 | Minimum	'
Derivative [Line Items]	'
Price Range	3.61
NYMEX Henry Hub, Waha, ANR-OK and CIG-Rockies Swaps | Natural gas | October-December 2014 | Maximum	'
Derivative [Line Items]	'
Price Range	6.47
NYMEX Henry Hub, Waha, ANR-OK and CIG-Rockies Swaps | Natural gas | 2015	'
Derivative [Line Items]	'
Volumes	16,219,300
Average Price	4.45
NYMEX Henry Hub, Waha, ANR-OK and CIG-Rockies Swaps | Natural gas | 2015 | Minimum	'
Derivative [Line Items]	'
Price Range	4.15
NYMEX Henry Hub, Waha, ANR-OK and CIG-Rockies Swaps | Natural gas | 2015 | Maximum	'
Derivative [Line Items]	'
Price Range	5.82
NYMEX Henry Hub, Waha, ANR-OK and CIG-Rockies Swaps | Natural gas | 2016	'
Derivative [Line Items]	'
Volumes	1,419,200
Average Price	4.3
NYMEX Henry Hub, Waha, ANR-OK and CIG-Rockies Swaps | Natural gas | 2016 | Minimum	'
Derivative [Line Items]	'
Price Range	4.12
NYMEX Henry Hub, Waha, ANR-OK and CIG-Rockies Swaps | Natural gas | 2016 | Maximum	'
Derivative [Line Items]	'
Price Range	5.3
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | October-December 2014	'
Derivative [Line Items]	'
Volumes	120,000
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | October-December 2014 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	4
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | October-December 2014 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	4.65
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | October-December 2014 | Call option | Short	'
Derivative [Line Items]	'
Average Strike Price	5.03
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2015	'
Derivative [Line Items]	'
Volumes	8,040,000
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2015 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	3.66
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2015 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	4.21
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2015 | Call option | Short	'
Derivative [Line Items]	'
Average Strike Price	5.01
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2016	'
Derivative [Line Items]	'
Volumes	5,580,000
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2016 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	3.75
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2016 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	4.25
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2016 | Call option | Short	'
Derivative [Line Items]	'
Average Strike Price	5.08
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2017	'
Derivative [Line Items]	'
Volumes	5,040,000
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2017 | Put option | Short	'
Derivative [Line Items]	'
Average Strike Price	3.75
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2017 | Put option | Long	'
Derivative [Line Items]	'
Average Strike Price	4.25
NYMEX Henry Hub Derivative Three-Way Collar Contracts | Natural gas | 2017 | Call option | Short	'
Derivative [Line Items]	'
Average Strike Price	5.53
Henry Hub NYMEX to Northwest Pipeline Natural Gas Differential Swaps | Natural gas | October-December 2014	'
Derivative [Line Items]	'
Volumes	3,000,000
Average Price	-0.09
Henry Hub NYMEX to Northwest Pipeline Natural Gas Differential Swaps | Natural gas | 2015	'
Derivative [Line Items]	'
Volumes	12,000,000
Average Price	-0.13
Henry Hub NYMEX to NGPL Midcon Natural Gas Differential Swaps [Member] | Natural gas | October-December 2014	'
Derivative [Line Items]	'
Volumes	240,000
Average Price	-0.1
Henry Hub NYMEX to NGPL Midcon Natural Gas Differential Swaps [Member] | Natural gas | 2015	'
Derivative [Line Items]	'
Volumes	480,000
Average Price	-0.15
Henry Hub NYMEX to California SoCal NGI Natural Gas Differential Swaps [Member] | Natural gas | October-December 2014	'
Derivative [Line Items]	'
Volumes	240,000
Average Price	0.29
Henry Hub NYMEX to California SoCal NGI Natural Gas Differential Swaps [Member] | Natural gas | 2015	'
Derivative [Line Items]	'
Volumes	240,000
Average Price	0.19
Henry Hub NYMEX to San Juan Basin Natural Gas Differential Swaps [Member] | Natural gas | October-December 2014	'
Derivative [Line Items]	'
Volumes	240,000
Average Price	-0.06
Henry Hub NYMEX to San Juan Basin Natural Gas Differential Swaps [Member] | Natural gas | 2015	'
Derivative [Line Items]	'
Volumes	480,000
Average Price	-0.12
Henry Hub NYMEX to West Texas WAHA Natural Gas Differential Swaps [Member] | Natural gas | October-December 2014	'
Derivative [Line Items]	'
Volumes	690,000
Average Price	-0.06
Henry Hub NYMEX to West Texas WAHA Natural Gas Differential Swaps [Member] | Natural gas | 2015	'
Derivative [Line Items]	'
Volumes	6,000,000
Average Price	-0.1
Interest rate swaps | Libor Swap All Tranches [Member]	'
Derivative [Line Items]	'
Estimated Fair Market Value	($2,602)
Interest rate swaps | Libor Swap Tranche 1	'
Derivative [Line Items]	'
Notional Amount	29,000
Fixed Rate	3.07%
Estimated Fair Market Value	-793
Interest rate swaps | Libor Swap Tranche 2	'
Derivative [Line Items]	'
Notional Amount	13,000
Fixed Rate	3.11%
Estimated Fair Market Value	-386
Interest rate swaps | Libor Swap Tranche 3	'
Derivative [Line Items]	'
Notional Amount	12,000
Fixed Rate	3.13%
Estimated Fair Market Value	-357
Interest rate swaps | Libor Swap Tranche 4	'
Derivative [Line Items]	'
Notional Amount	50,000
Fixed Rate	2.50%
Estimated Fair Market Value	($1,066)

Derivative_Financial_Instrumen5

Derivative Financial Instruments - Schedule of Derivatives, Gain (Loss) on Derivative Activity (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Cash settlements paid	'	'	$11,975	$4,666
Interest rate swaps | Not designated as hedging instrument	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Beginning fair value of interest rate swaps	-3,332	-6,478	-4,759	-9,547
Cash settlements paid	800	1,436	2,532	4,786
Ending fair value of interest rate swaps	-2,602	-5,690	-2,602	-5,690
Interest rate swaps | Not designated as hedging instrument | Interest expense	'	'	'	'
Derivative Instruments, Gain (Loss) [Line Items]	'	'	'	'
Total loss on interest rate swaps	($70)	($648)	($375)	($929)

Asset_Retirement_Obligation_De

Asset Retirement Obligation (Details) (USD $)	9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Changes in the ARO	'	'	'
Asset retirement obligation - beginning of period	$175,786	$162,183	$162,183
Liabilities incurred with properties acquired	50,487	'	10,969
Liabilities incurred with properties drilled	0	'	494
Liabilities settled during the period	-2,478	'	-2,441
Liabilities associated with properties sold	-4,804	9,853	-1,606
Current period accretion	5,698	'	6,187
Asset retirement obligation - end of period	$224,689	'	$175,786

Partners_Equity_Preferred_Unit

Partners' Equity - Preferred Units (Details) (USD $)

Sep. 30, 2014

12-May-14

Apr. 17, 2014

Sep. 30, 2014

Apr. 17, 2014

Sep. 30, 2014

Jun. 17, 2014

Jun. 17, 2014

Sep. 30, 2014

Jun. 04, 2014

Jun. 04, 2014

Sep. 30, 2014

Jun. 04, 2014

Jun. 04, 2014

Jun. 04, 2014

Jun. 04, 2014

Jun. 04, 2014

Jul. 01, 2014

In Millions, except Share data, unless otherwise specified

Series A Preferred Equity

Series A Preferred Equity

Series A Preferred Equity

Series A Preferred Equity

Series A Preferred Equity

Series B Preferred Equity

Series B Preferred Equity

Series B Preferred Equity

WPX acquisition

WPX acquisition

WPX acquisition

WPX acquisition

WPX acquisition

WPX acquisition

WPX acquisition

WPX acquisition

Over-allotment option

three-month LIBOR

three-month LIBOR

Immediate vesting

Ratable vesting

Ratable vesting

Forfeiture, first two anniversaries

Forfeiture, third anniversary

Unvested IDUs [Member]

Series B Preferred Equity

Class of Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock issuance (in shares)

'

'

2,000,000

'

'

'

7,000,000

'

'

'

'

'

'

'

'

'

'

200,000

Share price (in dollars per share)

'

'

'

'

$25

'

'

$25

'

'

'

'

'

'

'

'

'

'

Dividend rate

'

'

'

8.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Liquidation preference (in dollars per share)

$25

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional shares of underwriter purchase option

'

300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Variable dividend rate

'

'

'

'

'

5.24%

'

'

5.26%

'

'

'

'

'

'

'

'

'

Equity interests issuable (in shares)

'

'

'

'

'

'

'

'

'

300,000

'

100,000

10,000

'

'

'

200,000

'

Equity interests forfeiture (in shares)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

66,666

66,668

'

'

Additional cash consideration

'

'

'

'

'

'

'

'

'

'

'

'

'

$35.50

'

'

'

'

Conversion terms, minimum distribution per share

'

'

'

'

'

'

'

'

'

'

$0.90

'

'

'

'

'

'

'

Partners_Equity_Income_loss_pe

Partners' Equity - Income (loss) per unit (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]	'	'	'	'
Income (loss) available to unitholders	$59,066	($3,422)	$40,911	$11,627
Weighted average number of units outstanding (in shares)	57,406,000	57,275,000	57,363,000	57,200,000
Effect of dilutive securities:	'	'	'	'
Restricted and phantom units (in shares)	237,000	0	160,000	95,000
Weighted average units and potential common units outstanding (in shares)	57,643,000	57,275,000	57,523,000	57,295,000
Basic income (loss) per unit (in dollars per share)	$1.03	($0.06)	$0.71	$0.20
Diluted income (loss) per unit (in dollars per share)	$1.02	($0.06)	$0.71	$0.20
Phantom share units (PSUs)	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive restricted units excluded from computation of EPS	191,305	330,116	234,589	330,116
Restricted stock units (RSUs)	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive restricted units excluded from computation of EPS	151,189	425,195	185,396	425,195

UnitBased_Compensation_LTIP_Un

Unit-Based Compensation - LTIP, Unit Appreciation Rights and Unit Options (Details) (USD $)

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Unit appreciation rights (UARs)

Unit appreciation rights (UARs)

Unit appreciation rights (UARs)

Unit appreciation rights (UARs)

Unit appreciation rights (UARs)

Unit appreciation rights (UARs)

Restricted stock units (RSUs)

Restricted stock units (RSUs)

Phantom share units (PSUs)

Phantom share units (PSUs)

Long Term Incentive Plan

Long Term Incentive Plan

Long Term Incentive Plan

Long Term Incentive Plan

Long Term Incentive Plan

Ratable vesting

Ratable vesting

Cliff vesting

Cliff vesting

Unit option awards

Restricted stock units (RSUs)

Phantom share units (PSUs)

Unrestricted units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Units authorized for issuance (in shares)

'

'

'

'

'

'

'

'

'

'

'

2,000,000

'

'

'

'

Units issued as compensation (in shares)

'

'

'

'

'

'

'

'

'

'

'

1,254,655

266,014

534,298

323,965

130,378

Units issued as compensation. gross

'

216,774

'

111,600

156,650

105,174

77,506

'

'

'

'

'

'

'

'

'

Award vesting period

'

'

'

'3 years

'3 years

'3 years

'3 years

'

'

'

'

'

'

'

'

'

Unit award expiration period

'

'7 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share-based compensation expense

'

($23,700)

$700,000

'

'

'

'

$1,700,000

$1,700,000

$1,600,000

$700,000

'

'

'

'

'

Unrecognized compensation costs

'

$1,600,000

'

'

'

'

'

$5,500,000

'

'

'

'

'

'

'

'

Unrecognized compensation costs, weighted-average remaining period for recognition

'

'2 years 4 months 17 days

'

'

'

'

'

'2 years 4 months 24 days

'

'

'

'

'

'

'

'

Volatility

'

35.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share based compensation, forfeiture rate

'

4.60%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Annual distribution rate per unit (in dollars per share)

'

$2.44

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Annual interest rate

1.80%

1.80%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

UnitBased_Compensation_Option_

Unit-Based Compensation - Option and UAR Activity (Details) (Unit appreciation rights (UARs), USD $)	9 Months Ended
	Sep. 30, 2014
Unit appreciation rights (UARs)	'
Units (in shares)	'
Outstanding	627,043
Granted	216,774
Exercised	-136,585
Forfeited	-39,168
Outstanding	668,064
Options and UARs exercisable	200,089
Weighted-Average Exercise Price (in dollars per share)	'
Outstanding	$25.99
Granted	$28.85
Exercised	$24.34
Forfeited	$27.13
Outstanding	$27.19
Options and UARs exercisable	$25.27
Weighted-Average Remaining Contractual Term	'
Outstanding	'5 years 4 months 10 days
Options and UARs exercisable	'3 years 7 months 6 days
Aggregate Intrinsic Value	'
Outstanding	$1,723,770
Options and UARs exercisable	$910,458

UnitBased_Compensation_Status_

Unit-Based Compensation - Status of the Partnership's non-vested UARs (Details) (Unit appreciation rights (UARs), USD $)	9 Months Ended
	Sep. 30, 2014
Unit appreciation rights (UARs)	'
Number of Units	'
Non-vested at January 1, 2014	386,755
Granted	216,774
Vested	-97,386
Forfeited	-38,168
Non-vested at September 30, 2014	467,975
Weighted- Average Exercise Price	'
Non-vested at January 1, 2014	$27.21
Granted	$28.85
Vested	$26.89
Forfeited	$27.58
Non-vested at September 30, 2014	$28.01

UnitBased_Compensation_Weighte

Unit-Based Compensation - Weighted Average Assumptions (Details) (USD $)	9 Months Ended
	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Annual interest rate	1.80%
Stock Appreciation Rights (SARs) [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Expected life (years)	'5 years 4 months 10 days
Annual interest rate	1.80%
Annual distribution rate per unit (in dollars per share)	2.44
Volatility	35.00%

UnitBased_Compensation_Phantom

Unit-Based Compensation - Phantom, Board and Restricted Units (Details) (USD $)

15-May-14

14-May-13

Sep. 30, 2014

Sep. 30, 2013

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Mar. 31, 2013

Feb. 28, 2011

Sep. 21, 2009

Mar. 07, 2013

Mar. 31, 2013

Feb. 28, 2011

Mar. 07, 2013

Sep. 21, 2009

Sep. 21, 2009

Mar. 07, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Dec. 31, 2013

Dec. 31, 2013

15-May-14

14-May-13

15-May-14

14-May-13

Non-employee directors

Non-employee directors

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Subjective phantom share units (PSUs)

Subjective phantom share units (PSUs)

Subjective phantom share units (PSUs)

Objective phantom share units (PSUs)

Objective phantom share units (PSUs)

Objective phantom share units (PSUs)

Objective phantom share units (PSUs)

Objective phantom share units (PSUs)

Objective phantom share units (PSUs)

Objective phantom share units (PSUs)

Phantom share units (PSUs)

Phantom share units (PSUs)

Restricted stock units (RSUs)

Restricted stock units (RSUs)

Restricted stock units (RSUs)

Restricted stock units (RSUs)

Restricted stock units (RSUs)

Restricted stock units (RSUs)

Unrestricted units

Unrestricted units

Unrestricted units

Unrestricted units

Ratable vesting

Ratable vesting

Cliff vesting

Cliff vesting

Executive officers

Executive officers

Executive officers

Executive officers

Executive officers

Executive officers

Executive officers

Executive officers

Executive officers

Executive officers

Non-executive employees

Non-executive employees

Non-executive employees and certain executives

Non-executive employees and certain executives

Non-employee directors

Non-employee directors

Non-employee directors

Non-employee directors

Ratable vesting

Ratable vesting

Three-step process vesting

Three-step process vesting, each of first two steps

Cliff vesting

Ratable vesting

Ratable vesting

director

director

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Award vesting period

'

'

'

'

'

'3 years

'3 years

'3 years

'3 years

'

'

'3 years

'

'

'

'3 years

'3 years

'

'3 years

'

'

'

'

'

'3 years

'

'3 years

'

'

'

'

Award vesting percentage

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

50.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Award measurement period

'

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Granted (in shares)

'

'

216,774

'

'

'

'

'

'

117,197

46,430

'

'

102,572

76,723

'

'

'

'

'

'

'

'

108,415

'

85,728

'

3,628

3,715

'

'

Unvested units not included in consolidated balance sheet (in shares)

'

'

467,975

'

386,755

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

256,031

'

'

'

'

'

'

'

'

'

Individuals eligible for plan

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5

5

Share-based compensation expense

'

'

($23,700)

$700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$1,600,000

$700,000

$1,700,000

$1,700,000

'

'

'

'

'

'

'

'

Unrecognized compensation costs

'

'

$1,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$5,500,000

'

'

'

'

'

'

'

'

'

Unrecognized compensation costs, period of recognition

'

'

'2 years 4 months 17 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'2 years 4 months 24 days

'

'

'

'

'

'

'

'

'

Value of each unit at issuance (in dollars per share)

$27.50

$27.39

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Subsidiary_Guarantors_Details

Subsidiary Guarantors (Details) (Senior notes, USD $)	12 Months Ended
In Millions, unless otherwise specified	8-May-14	Sep. 30, 2014	Mar. 18, 2014
	offering
Senior notes	'	'	'
Debt Instrument [Line Items]	'	'	'
Number of private offerings	2	'	'
Aggregate principal amount	'	'	$250
Percent of subsidiaries owned	'	100.00%	'

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	Oct. 20, 2014	Oct. 08, 2014	Oct. 08, 2014	Oct. 08, 2014	Apr. 02, 2014	Oct. 01, 2014
	Subsequent event	Subsequent event	Subsequent event	Subsequent event	Credit facility due 2019	Credit facility due 2019
		Limited Partner	Limited Partner	Limited Partner		Subsequent event
				Over-allotment option
Subsequent Event [Line Items]	'	'	'	'	'	'
Maximum borrowing capacity	'	'	'	'	$1,500,000,000	$950,000,000
Stock issuance (in shares)	'	11,500,000	'	1,500,000	'	'
Share price (in dollars per share)	'	'	$26.43	'	'	'
Proceeds from offering	'	$303,900,000	'	'	'	'
Distributions declared and paid (in dollars per share)	$0.61	'	'	'	'	'