TRANSACTIONS WITH AFFILIATES	3 Months Ended
TRANSACTIONS WITH AFFILIATES	Mar. 31, 2019
Related Party Transactions [Abstract]
TRANSACTIONS WITH AFFILIATES	TRANSACTIONS WITH AFFILIATES Revenues The Company has contracted to provide services including gas gathering, compression, processing, transportation, and NGL transportation, pursuant to acreage dedications provided by Apache, comprising the entire Alpine High acreage. In accordance with the terms of these agreements, the Company receives prescribed fees based on the type and volume of product for which the services are provided. For all of the periods presented, the Company’s only customer was Apache, although Altus Midstream is pursuing contracts with third-parties that could be accommodated by existing and planned capacity. Revenues generated under these agreements are presented on the Company’s statement of consolidated operations as “Midstream services revenue — affiliate.” Revenues earned that have not yet been invoiced to Apache are presented on the Company’s consolidated balance sheet as “Revenue receivables.” Cost and Expenses The Company has no employees, and prior to the Business Combination, the Company had no banking or cash management facilities prior to the Business Combination. As such, the Company has contracted with Apache to receive certain operational, maintenance, and management services. In accordance with the terms of these agreements, the Company incurred general and administrative (G&A) expenses of $1.6 million for each of the three months ended March 31, 2019 and 2018, including expenses related to the operational service agreement and COMA as further described below. Operations and maintenance expenses of $2.9 million and $2.3 million were also incurred for the three months ended March 31, 2019 and 2018, respectively, pursuant to these agreements. Further information on the related-party agreements in place during the period is provided below. Operational Services Agreement Prior to the Business Combination, Apache provided operations, maintenance and management services to Altus Midstream Operating, pursuant to a service agreement (the Services Agreement). In accordance with the terms of the Services Agreement, Apache received a fixed fee per month for its overhead and indirect costs incurred on behalf of Altus Midstream Operating. All costs incurred by Altus Midstream Operating were paid by Apache. Construction, Operations and Maintenance Agreement At the closing of the Business Combination, the Company entered into the COMA with Apache, which superseded the Services Agreement. Under the terms of the COMA, Apache will provide certain services related to the design, development, construction, operation, management and maintenance of certain gathering, processing and other midstream assets, on behalf of the Company. In return, the Company will pay fees to Apache of (i) $3.0 million for the period beginning on the execution of the COMA at the closing of the Business Combination through December 31, 2019, (ii) $5.0 million for the period of January 1, 2020 through December 31, 2020, (iii) $7.0 million for the period of January 1, 2021 through December 31, 2021 and (iv) $9.0 million annually thereafter, as may be adjusted upwards based on actual incurred costs, until terminated. The annual fee was negotiated as part of the Business Combination to reimburse Apache for indirect costs incurred in performing administrative corporate functions for the Company, including services for information technology, risk management, corporate planning, accounting, cash management, and others. In addition, Apache may be reimbursed for certain internal costs and third-party costs directly incurred in connection with its role as service provider under the COMA. Apache records costs directly associated with midstream activity, where substantially all the services are rendered for Altus Midstream, to unique midstream cost centers that are subsequently charged to Altus Midstream on a monthly basis. Lease Agreement Concurrent with the closing of the Business Combination, Altus Midstream entered into an operating lease agreement with Apache (the Lease Agreement) relating to the use of certain office buildings, warehouse and storage facilities located in Reeves County, Texas. Under the terms of the Lease Agreement, Altus Midstream shall pay to Apache on a monthly basis the sum of (i) a base rental charge of $44,500 and (ii) an amount based on Apache’s estimate of the annual costs it expects to incur in connection with the ownership, operation, repair, and/or maintenance of the facilities. The Company incurred total expenses of $0.2 million for the three months ended March 31, 2019 in relation to the Lease Agreement, which are included within operations and maintenance expenses. Unpaid amounts accrue interest until settled. The initial term of the Lease Agreement is for four years and may be extended by Altus Midstream for three additional, consecutive periods of twenty-four months. Capitalized Interest Prior to the Business Combination, the Company’s operations were funded entirely by contributions from Apache. Accordingly, Apache allocated a portion of interest on its corporate debt in determining capitalized interest associated with the development of Altus Midstream Operating. Commensurate with Apache’s calculation, interest is capitalized as part of the historical cost of developing and constructing assets. Significant midstream development assets that have not commenced operations qualify for interest capitalization. The associated capitalized interest was determined by multiplying Apache’s weighted-average borrowing cost of debt by the average amount of qualifying midstream assets. Following the closing the Business Combination, capitalized interest is determined based on interest expense incurred by Altus Midstream. The amount of interest capitalized was $0.4 million and $2.5 million for the three months ended March 31, 2019 and 2018, respectively.