OIL AND NATURAL GAS PROPERTIES ACQUISITIONS Acquisitions of proved oil and natural gas properties and working interests are considered business combinations and are recorded at their estimated fair value as of the acquisition date. Acquisitions of unproved oil and natural gas properties are considered asset acquisitions and are recorded at cost. 2019 Acquisitions During the three months ended March 31, 2019 , the Partnership closed on multiple acquisitions of mineral and royalty interests for total consideration of $20.9 million . Acquisitions that included proved oil and natural gas properties were considered business combinations and were primarily located in the Permian Basin. These acquisitions were funded with borrowings under the Credit Facility (as defined in Note 7 - Credit Facility) and funds from operating activities. Acquisition related costs of less than $0.1 million were expensed and included in the General and administrative expense line item of the consolidated statement of operations for the three months ended March 31, 2019 . The following table summarizes these acquisitions which were considered business combinations: Assets Acquired Consideration Paid Proved Unproved Net Working Capital Total Fair Value Cash (in thousands) February $ 173 $ 8,437 $ 1 $ 8,611 $ 8,611 March 24   24 24 Total fair value $ 197 $ 8,437 $ 1 $ 8,635 $ 8,635 In addition, during the three months ended March 31, 2019 , the Partnership acquired mineral and royalty interests in unproved oil and natural gas properties from various sellers for an aggregate of $12.3 million . These acquisitions were considered asset acquisitions and were primarily located in East Texas. The cash portion of the consideration paid for these acquisitions of $11.4 million was funded with borrowings under the Credit Facility and funds from operating activities, and $0.9 million was funded through the issuance of common units of the Partnership based on the fair values of the common units issued on the acquisition dates. 2018 Acquisitions During the year ended December 31, 2018 , the Partnership closed on multiple acquisitions of mineral and royalty interests for total consideration of $149.9 million . Acquisitions that included proved oil and natural gas properties were considered business combinations and were primarily located in the Permian Basin. The cash portion of the consideration paid for these acquisitions was funded with borrowings under the Credit Facility and funds from operating activities. Acquisition related costs of $0.2 million were expensed and included in the General and administrative expense line item of the consolidated statement of operations for the year ended December 31, 2018 . The following table summarizes these acquisitions which were considered business combinations: Assets Acquired Consideration Paid Proved Unproved Net Working Capital Total Fair Value Cash Fair Value of Common Units Issued (in thousands) March $ 984 $ 21,452 $ 133 $ 22,569 $ 22,569 $  June 883 13,688 8 14,579 14,579  July 4,349 7,944 215 12,508 3,764 8,744 August 5,000 34,673 74 39,747 26,461 13,286 September 1,176   1,176 1,176  November 1,166   1,166 1,166  Total fair value $ 13,558 $ 77,757 $ 430 $ 91,745 $ 69,715 $ 22,030 In addition, during 2018, the Partnership acquired mineral and royalty interests in unproved oil and natural gas properties from various sellers for an aggregate of $58.2 million . These acquisitions were considered asset acquisitions and were primarily located in East Texas and the Permian Basin. The cash portion of the consideration paid for these acquisitions of $57.6 million was funded with borrowings under the Credit Facility and funds from operating activities, and $0.6 million was funded through the issuance of common units of the Partnership based on the fair values of the common units issued on the acquisition dates. During 2018, the Partnership acquired the remaining noncontrolling interest in certain subsidiaries for $1.7 million in cash and merged the subsidiaries into its existing structure. Farmout Agreements Canaan Farmout On February 21, 2017, the Partnership announced that it had entered into a farmout agreement with Canaan Resource Partners ("Canaan") which covers certain Haynesville and Bossier shale acreage in San Augustine County, Texas operated by XTO Energy Inc., a subsidiary of Exxon Mobil Corporation. The Partnership has an approximate 50% working interest in the acreage and is the largest mineral owner. A total of 20 wells were drilled over an initial phase, beginning with wells spud after January 1, 2017. Canaan has elected to participate in an additional phase that began in September 2018 and will continue for the lesser of 2 years or until 20 wells have been drilled. After the completion of the second phase, Canaan will have the option to elect to participate in a similar third phase. During the first three phases of the agreement, Canaan commits on a phase-by-phase basis and funds 80% of the Partnership's drilling and completion costs and is assigned 80% of the Partnership's working interests in such wells ( 40% working interest on an 8/8ths basis) as the wells are drilled. After the third phase, Canaan can earn 40% of the Partnerships working interest ( 20% working interest on an 8/8ths basis) in additional wells drilled in the area by continuing to fund 40% of the Partnership's costs for those wells on a well-by-well basis. The Partnership will receive an overriding royalty interest (ORRI) before payout and an increased ORRI after payout on all wells drilled under the agreement. From the inception of the agreement through March 31, 2019 , the Partnership has received $86.4 million from Canaan under the agreement. As of March 31, 2019 , the Partnership had assigned to Canaan working interests in certain wells drilled and completed, and as such, $8.9 million of the farmout reimbursements received from Canaan are included in the Other long-term liabilities line item of the consolidated balance sheet. Pivotal Farmout On November 21, 2017, the Partnership entered into a farmout agreement with Pivotal Petroleum Partners (Pivotal), a portfolio company of Tailwater Capital, LLC. The farmout agreement covers substantially all of the Partnership's remaining working interests under active development in the Shelby Trough area of East Texas, targeting the Haynesville and Bossier shale acreage (after giving effect to the Canaan Farmout), until November 2025. In wells operated by XTO Energy Inc. in San Augustine County, Texas, Pivotal will earn the Partnership's remaining working interest not covered by the Canaan Farmout ( 10% working interest on an 8/8th basis), as well as 100% of the Partnership's working interests (ranging from approximately 12.5% to 25% on an 8/8ths basis) in wells operated by its other major operator in San Augustine and Angelina counties, Texas. Initially, Pivotal is obligated to fund the development of up to 80 wells across several development areas and then has options to continue funding the Partnership's working interest across those areas for the duration of the farmout agreement. Pivotal will fund designated groups of wells. Once Pivotal achieves a specified payout for a designated well group, the Partnership will obtain a majority of the original working interest in such well group. From the inception of the agreement through March 31, 2019 , the Partnership received $86.8 million from Pivotal under the agreement. As of March 31, 2019 , the Partnership had assigned to Pivotal working interests in certain wells drilled and completed, and as such, $63.1 million of the farmout reimbursements received from Pivotal are included in the Other long-term liabilities line item of the consolidated balance sheet. As of December 31, 2018 , $11.6 million and $41.2 million were included in the Other long-term liabilities line item of the consolidated balance sheet related to the farmout agreements with Canaan and Pivotal, respectively.