Basis of Presentation	6 Months Ended
Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The unaudited interim consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (or GAAP). These financial statements include the accounts of Teekay Offshore Partners L.P., which is a limited partnership organized under the laws of the Republic of the Marshall Islands, and its wholly-owned or controlled subsidiaries (collectively, the Partnership). Unless the context otherwise requires, the terms "we," "us," or "our," as used herein, refer to the Partnership. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Certain information and footnote disclosures required by GAAP for complete annual financial statements have been omitted and, therefore, these interim financial statements should be read in conjunction with the Partnership’s audited consolidated financial statements for the year ended December 31, 2017, which are included in the Partnership’s Annual Report on Form 20-F, filed with the U.S. Securities and Exchange Commission (or SEC) on March 21, 2018. In the opinion of management of the Partnership’s general partner, Teekay Offshore GP L.L.C. (or the general partner), these interim unaudited consolidated financial statements reflect all adjustments, which are of a normal recurring nature, necessary to present fairly, in all material respects, the Partnership’s consolidated financial position, results of operations, changes in total equity and cash flows for the interim periods presented. The results of operations for the interim periods presented are not necessarily indicative of those for a full fiscal year. Historically, the utilization of shuttle tankers in the North Sea is higher in the winter months as favorable weather conditions in the summer months provide opportunities for repairs and maintenance to the Partnership’s vessels and the offshore oil platforms. Downtime for repairs and maintenance generally reduces oil production and, thus, transportation requirements. Intercompany balances and transactions have been eliminated upon consolidation. The Partnership's shuttle tankers are comprised of two components: i) a conventional tanker (or the tanker component) and ii) specialized shuttle equipment (or the shuttle component). The Partnership differentiates these two components on the principle that a shuttle tanker can also operate as a conventional tanker without the use of the shuttle component. The economics of this alternate use depend on the supply and demand fundamentals in the two segments. Historically, the Partnership has assessed the useful life of the tanker component as being 25 years and the shuttle component as being 20 years. During the six months ended June 30, 2018, the Partnership has considered challenges associated with shuttle tankers approaching 20 years of age in recent years and has reassessed the useful life of the tanker component to 20 years. This change in estimate, commencing January 1, 2018, affects 21 vessels in the Partnership's shuttle tanker fleet. The effect of this change in estimate was an increase in depreciation and amortization expense and net loss of $4.3 million and $8.5 million, or $0.01 and $0.02 per basic and diluted common unit, respectively, for the three and six months ended June 30, 2018.

Basis of Presentation

The unaudited interim consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (or GAAP). These financial statements include the accounts of Teekay Offshore Partners L.P., which is a limited partnership organized under the laws of the Republic of the Marshall Islands, and its wholly-owned or controlled subsidiaries (collectively, the Partnership). Unless the context otherwise requires, the terms "we," "us," or "our," as used herein, refer to the Partnership.

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

Certain information and footnote disclosures required by GAAP for complete annual financial statements have been omitted and, therefore, these interim financial statements should be read in conjunction with the Partnership’s audited consolidated financial statements for the year ended December 31, 2017, which are included in the Partnership’s Annual Report on Form 20-F, filed with the U.S. Securities and Exchange Commission (or SEC) on March 21, 2018. In the opinion of management of the Partnership’s general partner, Teekay Offshore GP L.L.C. (or the general partner), these interim unaudited consolidated financial statements reflect all adjustments, which are of a normal recurring nature, necessary to present fairly, in all material respects, the Partnership’s consolidated financial position, results of operations, changes in total equity and cash flows for the interim periods presented. The results of operations for the interim periods presented are not necessarily indicative of those for a full fiscal year. Historically, the utilization of shuttle tankers in the North Sea is higher in the winter months as favorable weather conditions in the summer months provide opportunities for repairs and maintenance to the Partnership’s vessels and the offshore oil platforms. Downtime for repairs and maintenance generally reduces oil production and, thus, transportation requirements. Intercompany balances and transactions have been eliminated upon consolidation.

The Partnership's shuttle tankers are comprised of two components: i) a conventional tanker (or the tanker component) and ii) specialized shuttle equipment (or the shuttle component). The Partnership differentiates these two components on the principle that a shuttle tanker can also operate as a conventional tanker without the use of the shuttle component. The economics of this alternate use depend on the supply and demand fundamentals in the two segments. Historically, the Partnership has assessed the useful life of the tanker component as being 25 years and the shuttle component as being 20 years. During the six months ended June 30, 2018, the Partnership has considered challenges associated with shuttle tankers approaching 20 years of age in recent years and has reassessed the useful life of the tanker component to 20 years. This change in estimate, commencing January 1, 2018, affects 21 vessels in the Partnership's shuttle tanker fleet. The effect of this change in estimate was an increase in depreciation and amortization expense and net loss of $4.3 million and $8.5 million, or $0.01 and $0.02 per basic and diluted common unit, respectively, for the three and six months ended June 30, 2018.