Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited interim consolidated financial statements (or unaudited consolidated financial statements) have been prepared in accordance with United States generally accepted accounting principles (or GAAP). These unaudited consolidated financial statements include the accounts of Teekay Tankers Ltd., its wholly-owned subsidiaries, equity-accounted joint venture and any variable interest entities (or VIEs) of which it is the primary beneficiary (collectively, the Company). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the unaudited consolidated 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 unaudited consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements for the year ended December 31, 2019, filed on Form 20-F with the U.S. Securities and Exchange Commission (or the SEC) on April 15, 2020. In the opinion of management, these unaudited consolidated financial statements reflect all adjustments, consisting solely of a normal recurring nature, necessary to present fairly, in all material respects, the Company’s unaudited consolidated financial position, results of operations, 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. Intercompany balances and transactions have been eliminated upon consolidation. In March 2020, the World Health Organization declared the outbreak of a novel coronavirus (or COVID-19) as a pandemic. Given the dynamic nature of these circumstances, the full extent to which the COVID-19 pandemic may have direct or indirect impact on the Company's business and the related financial reporting implications cannot be reasonably estimated at this time, although the pandemic could materially affect the Company's business, results of operations and financial condition in the future. COVID-19 has resulted and may continue to result in a significant decline in global demand for oil. As the Company's business includes the transportation of crude oil and refined petroleum products on behalf of customers, any significant decrease in demand for the cargo the Company transports could adversely affect demand for the Company's vessels and services. Spot tanker rates have come under pressure since mid-May 2020 as a result of record OPEC+ oil production cuts and lower production from other oil producing countries, which reduced crude exports, and the unwinding of floating storage. COVID-19 has also been a contributing factor to the decline in short-term charter rates and the increase in certain crewing-related costs, which has had an impact on our cash flows, and was a contributing factor to the write-down of certain tankers during the nine months ended September 30, 2020 as described in Note 15 - Write-down and Loss on Sale of Assets and the reduction in certain tax accruals as described in Note 10 - Income Tax (Expense) Recovery. Voyage Charter Revenues and Expenses Voyage expenses incurred that are recoverable from the Company's customers in connection with its voyage charter contracts are reflected in voyage charter revenues and voyage expenses. The Company recast prior periods to reflect this presentation. This had the impact of increasing both voyage charter revenues and voyage expenses by $5.1 million and $15.5 million for the three and nine months ended September 30, 2019, respectively. Reverse Stock Split The per share amounts for all periods presented have been adjusted to reflect a one-for-eight reverse stock split completed in November 2019.