TRANSACTIONS WITH AFFILIATES	3 Months Ended
TRANSACTIONS WITH AFFILIATES	Mar. 31, 2020
Related Party Transactions [Abstract]
TRANSACTIONS WITH AFFILIATES	TRANSACTIONS WITH AFFILIATES Revenues The Company has contracted to provide services including gas gathering, compression, processing, transmission, and NGL transmission, 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 significant customer was Apache. 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.” Refer to Note 3—Revenue Recognition for further discussion. Cost and Expenses The Company has no employees, and prior to the Business Combination, the Company had no banking or cash management facilities. 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 operations and maintenance expenses of $1.4 million and $2.9 million for the three months ended March 31, 2020 and 2019, respectively. The Company incurred general and administrative (G&A) expenses of $2.0 million and $1.6 million for the three months ended March 31, 2020 and 2019, respectively, including expenses related to the operational services agreement and the COMA as further described below. Further information on the related-party operating lease agreement in place during the period is also provided below. Construction, Operations and Maintenance Agreement At the closing of the Business Combination, the Company entered into the COMA with Apache. Under the terms of the COMA, Apache provides 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 paid or 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, adjusted based on actual internal overhead and general and administrative costs incurred, until terminated. The annual fee was negotiated as part of the Business Combination to reimburse Apache for indirect costs of 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 incurred in connection with its role as service provider under the COMA. Costs incurred by Apache directly associated with midstream activity, where substantially all the services are rendered for Altus Midstream, are charged to Altus Midstream on a monthly basis. The COMA stipulates that the Company shall provide reimbursement of amounts owing to Apache attributable to a particular month by no later than the last day of the immediately following month. Unpaid amounts accrue interest until settled. The COMA will continue to be effective until terminated (i) upon the mutual consent of Altus and Apache, (ii) by either of Altus and Apache, at its option, upon 30 days’ prior written notice in the event Apache or an affiliate no longer owns a direct or indirect interest in at least 50 percent of the voting or other equity securities of Altus, or (iii) by Altus if Apache fails to perform any of its covenants or obligations due to willful misconduct of certain key personnel and such failure has a material adverse financial impact on Altus. 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 $0.3 million and $0.2 million for the three months ended March 31, 2020 and 2019, respectively, 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.