Dropdown of DevCo Ownership Interests	12 Months Ended
Dec. 31, 2018
Business Combinations [Abstract]
Dropdown of DevCo Ownership Interests	Dropdown of DevCo Ownership Interests On November 19, 2018, the Partnership completed transactions contemplated by a contribution agreement (the “Contribution Agreement”) dated as of November 7, 2018, with OMS Holdings LLC, OMS, OMP GP LLC, OMP Operating, and for certain limited purposes set forth therein, Oasis Petroleum. Pursuant to the Contribution Agreement, Oasis Petroleum caused OMS to contribute to OMP Operating, as the Partnership’s designee, (a) an additional 15% limited liability company interest in Bobcat DevCo, and (b) an additional 30% limited liability company interest in Beartooth DevCo (collectively, the “Contributed Assets”) for consideration of approximately $251.4 million (the “Purchase Price”), consisting of approximately $172.4 million in cash and 3,950,000 common units, representing limited partner interests in the Partnership (the “Dropdown Acquisition”). The Purchase Price includes post-effective date adjustments of approximately $1.4 million. The Partnership funded the cash portion of the Purchase Price with a combination of borrowings under the Revolving Credit Facility and proceeds from its public offering of common units. Following the Dropdown Acquisition, the Partnership owns 25% of the limited liability company interests of Bobcat DevCo and 70% of the limited liability company interests of Beartooth DevCo. The effective date of the Dropdown Acquisition was July 1, 2018, and the Dropdown Acquisition closed on November 19, 2018. Prior to the Dropdown Acquisition, the Contributed Assets were reflected as non-controlling interests in the consolidated financial statements. In accordance with FASB authoritative guidance under ASC 810-10 for non-controlling interests in a common control transaction, the Partnership accounted for the Dropdown Acquisition as an equity transaction and adjusted the carrying amount of non-controlling interests in the consolidated financial statements to reflect the change in ownership interests. Furthermore, as the Partnership acquired additional interests in previously consolidated subsidiaries, the Dropdown Acquisition did not result in a change in reporting entity, as defined under the FASB Accounting Standards Codification Topic 805, Business Combinations, and was accounted for on a prospective basis.

Dropdown of DevCo Ownership Interests

On November 19, 2018, the Partnership completed transactions contemplated by a contribution agreement (the “Contribution Agreement”) dated as of November 7, 2018, with OMS Holdings LLC, OMS, OMP GP LLC, OMP Operating, and for certain limited purposes set forth therein, Oasis Petroleum. Pursuant to the Contribution Agreement, Oasis Petroleum caused OMS to contribute to OMP Operating, as the Partnership’s designee, (a) an additional 15% limited liability company interest in Bobcat DevCo, and (b) an additional 30% limited liability company interest in Beartooth DevCo (collectively, the “Contributed Assets”) for consideration of approximately $251.4 million (the “Purchase Price”), consisting of approximately $172.4 million in cash and 3,950,000 common units, representing limited partner interests in the Partnership (the “Dropdown Acquisition”). The Purchase Price includes post-effective date adjustments of approximately $1.4 million. The Partnership funded the cash portion of the Purchase Price with a combination of borrowings under the Revolving Credit Facility and proceeds from its public offering of common units. Following the Dropdown Acquisition, the Partnership owns 25% of the limited liability company interests of Bobcat DevCo and 70% of the limited liability company interests of Beartooth DevCo. The effective date of the Dropdown Acquisition was July 1, 2018, and the Dropdown Acquisition closed on November 19, 2018.

Prior to the Dropdown Acquisition, the Contributed Assets were reflected as non-controlling interests in the consolidated financial statements. In accordance with FASB authoritative guidance under ASC 810-10 for non-controlling interests in a common control transaction, the Partnership accounted for the Dropdown Acquisition as an equity transaction and adjusted the carrying amount of non-controlling interests in the consolidated financial statements to reflect the change in ownership interests. Furthermore, as the Partnership acquired additional interests in previously consolidated subsidiaries, the Dropdown Acquisition did not result in a change in reporting entity, as defined under the FASB Accounting Standards Codification Topic 805, Business Combinations, and was accounted for on a prospective basis.