Subsequent Events	6 Months Ended
Jun. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On July 2, 2015, Legacy entered into a Development Agreement (the “Development Agreement”) with Jupiter JV, LP (“Investor”), which was formed by certain of TPG Special Situations Partners’ investment funds. Pursuant to the Development Agreement, Legacy and Investor will participate in the funding, exploration, development and operation of certain of Legacy’s currently undeveloped oil and gas properties covering approximately 6,000 net acres, restricted to certain depths, located in the University Block, RTF Block and Lea Hamon Block in the Permian Basin (collectively, the “Subject Assets”). Concurrently with the Development Agreement, Legacy and Investor entered into an Asset Acquisition Agreement pursuant to which Legacy conveyed to Investor an undivided 87.5% of Legacy's working interest in the Subject Assets subject to re-assignment, reversion and other adjustments. Legacy and Investor will establish tranches of proposed horizontal locations, with Investor funding 95% of Legacy's drilling and completion costs and receiving 87.5% of certain of Legacy's interests in any wells in such tranche until it achieves a 1.0x return on investment ("ROI Hurdle"). Legacy will fund 5% of the drilling and completion costs and retain 12.5% of certain of its interests prior to the ROI Hurdle. Upon achievement of the ROI Hurdle, Investor will revert to 63% of Legacy's initial interest while Legacy will revert to 37% until Investor achieves a 15% internal rate of return ("IRR Hurdle"). Upon achievement of the IRR Hurdle, Investor will revert to 15% of Legacy's initial interest while Legacy will revert to 85%, and all the remaining undeveloped interests will revert to Legacy but remain available for future development under the Development Agreement. On July 3, 2015, Legacy entered into a Membership Interest Purchase and Sale Agreement (the “WGR Purchase Agreement”) with WGR Operating LP (“WGR”), a subsidiary of Western Gas Partners LP, which is a master limited partnership formed by Anadarko Petroleum Corporation. Pursuant to the WGR Purchase Agreement, Legacy acquired from WGR 100% of the issued and outstanding limited liability company membership interests in Dew Gathering LLC, a Texas limited liability company, which owns directly and indirectly natural gas gathering and processing assets (the “G&P Assets”) in Anderson, Freestone, Houston, Leon, Limestone and Robertson Counties, Texas, for a purchase price of $154 million, subject to customary adjustments. In addition, on July 3, 2015, Legacy entered into a Purchase and Sale Agreement (together with the “WGR Purchase Agreement,” the “Agreements”) with Anadarko E&P Onshore LLC (“Anadarko”), a subsidiary of Anadarko Petroleum Corporation, pursuant to which Legacy acquired various oil and natural gas properties and associated exploration and production assets (the “E&P Assets”) from Anadarko for a purchase price of $286 million, subject to customary adjustments. The G&P Assets service the E&P Assets. Both the WGR and Anadarko purchases closed on July 31, 2015 and were funded with borrowings under Legacy's revolving credit facility. Legacy is currently determining the fair value of assets acquired and liabilities assumed in each purchase. On July 21, 2015, Legacy’s board of directors approved a distribution of $0.35 per unit payable on August 14, 2015 to unitholders of record on July 31, 2015. On July 21, 2015, Legacy announced that its general partner had declared a monthly cash distribution for both its Series A Preferred Units and its Series B Preferred Units of $0.166667 per unit payable on August 17, 2015 to unitholders of record on August 3, 2015. On August 5, 2015, Legacy entered into the Fifth Amendment to the Current Credit Agreement (the “Fifth Amendment”). Pursuant to the Fifth Amendment, the borrowing base under the Current Credit Agreement was increased from $700 million to $950 million and an additional lender was added to the agreement. As of August 5, 2015, Legacy had approximately $554 million drawn under the Current Credit Agreement, leaving approximately $396 million of current availability.

Subsequent Events

On July 2, 2015, Legacy entered into a Development Agreement (the “Development Agreement”) with Jupiter JV, LP (“Investor”), which was formed by certain of TPG Special Situations Partners’ investment funds. Pursuant to the Development Agreement, Legacy and Investor will participate in the funding, exploration, development and operation of certain of Legacy’s currently undeveloped oil and gas properties covering approximately 6,000 net acres, restricted to certain depths, located in the University Block, RTF Block and Lea Hamon Block in the Permian Basin (collectively, the “Subject Assets”). Concurrently with the Development Agreement, Legacy and Investor entered into an Asset Acquisition Agreement pursuant to which Legacy conveyed to Investor an undivided 87.5% of Legacy's working interest in the Subject Assets subject to re-assignment, reversion and other adjustments. Legacy and Investor will establish tranches of proposed horizontal locations, with Investor funding 95% of Legacy's drilling and completion costs and receiving 87.5% of certain of Legacy's interests in any wells in such tranche until it achieves a 1.0x return on investment ("ROI Hurdle"). Legacy will fund 5% of the drilling and completion costs and retain 12.5% of certain of its interests prior to the ROI Hurdle. Upon achievement of the ROI Hurdle, Investor will revert to 63% of Legacy's initial interest while Legacy will revert to 37% until Investor achieves a 15% internal rate of return ("IRR Hurdle"). Upon achievement of the IRR Hurdle, Investor will revert to 15% of Legacy's initial interest while Legacy will revert to 85%, and all the remaining undeveloped interests will revert to Legacy but remain available for future development under the Development Agreement.

On July 3, 2015, Legacy entered into a Membership Interest Purchase and Sale Agreement (the “WGR Purchase Agreement”) with WGR Operating LP (“WGR”), a subsidiary of Western Gas Partners LP, which is a master limited partnership formed by Anadarko Petroleum Corporation. Pursuant to the WGR Purchase Agreement, Legacy acquired from WGR 100% of the issued and outstanding limited liability company membership interests in Dew Gathering LLC, a Texas limited liability company, which owns directly and indirectly natural gas gathering and processing assets (the “G&P Assets”) in Anderson, Freestone, Houston, Leon, Limestone and Robertson Counties, Texas, for a purchase price of $154 million, subject to customary adjustments. In addition, on July 3, 2015, Legacy entered into a Purchase and Sale Agreement (together with the “WGR Purchase Agreement,” the “Agreements”) with Anadarko E&P Onshore LLC (“Anadarko”), a subsidiary of Anadarko Petroleum Corporation, pursuant to which Legacy acquired various oil and natural gas properties and associated exploration and production assets (the “E&P Assets”) from Anadarko for a purchase price of $286 million, subject to customary adjustments. The G&P Assets service the E&P Assets. Both the WGR and Anadarko purchases closed on July 31, 2015 and were funded with borrowings under Legacy's revolving credit facility. Legacy is currently determining the fair value of assets acquired and liabilities assumed in each purchase.

On July 21, 2015, Legacy’s board of directors approved a distribution of $0.35 per unit payable on August 14, 2015 to unitholders of record on July 31, 2015.

On July 21, 2015, Legacy announced that its general partner had declared a monthly cash distribution for both its Series A Preferred Units and its Series B Preferred Units of $0.166667 per unit payable on August 17, 2015 to unitholders of record on August 3, 2015.

On August 5, 2015, Legacy entered into the Fifth Amendment to the Current Credit Agreement (the “Fifth Amendment”). Pursuant to the Fifth Amendment, the borrowing base under the Current Credit Agreement was increased from $700 million to $950 million and an additional lender was added to the agreement. As of August 5, 2015, Legacy had approximately $554 million drawn under the Current Credit Agreement, leaving approximately $396 million of current availability.