Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying unaudited condensed consolidated interim financial statements include the accounts of Grubhub Inc. and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and in accordance with the rules and regulations of the United States Securities and Exchange Commission (the “SEC”). Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. These unaudited condensed consolidated interim financial statements include all wholly-owned subsidiaries and reflect all normal and recurring adjustments, as well as any other than normal adjustments, that are, in the opinion of management, necessary for a fair presentation of the results for the interim periods and should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019 filed with the SEC on February 28, 2020 (the “2019 Form 10-K”). All significant intercompany transactions have been eliminated in consolidation. Operating results for the three and six months ended June 30, 2020 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2020.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in accordance with GAAP requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and the related disclosures at the date of the financial statements, as well as the reported amounts of revenue and expenses during the periods presented. These estimates, judgments and assumptions take into account historical and forward-looking factors that the Company believes are reasonable including, but not limited to, the potential impacts arising from the COVID-19 pandemic and measures implemented to prevent its spread. As the extent and duration of the impacts from the COVID-19 pandemic remain unclear, the Company’s estimates and assumptions may evolve as conditions change. Significant items subject to such estimates, judgments and assumptions include revenue recognition, website and internal-use software development costs, goodwill, valuation and recoverability of intangible assets with finite lives and other long-lived assets, stock-based compensation, and income taxes. Actual results could differ significantly from these estimates.
Changes in Accounting Principle and Recently Issued Accounting Pronouncements	Changes in Accounting Principle See “Recently Issued Accounting Pronouncements” below for a description of accounting principle changes adopted during the six months ended June 30, 2020 related to credit losses. There have been no other material changes to the Company’s significant accounting policies described in the 2019 Form 10-K. Recently Issued Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2016-13, “Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). ASU 2016-13 introduces a new forward-looking approach, based on expected losses, to estimate credit losses on certain types of financial instruments, including trade receivables and held-to-maturity debt securities, which requires entities to incorporate considerations of historical information, current information and reasonable and supportable forecasts. This ASU also expands disclosure requirements. ASU 2016-13 was effective for and adopted by the Company in the first quarter of 2020. The guidance was applied using the modified-retrospective approach. The adoption of ASU 2016-13 did not have a material impact on the Company’s consolidated financial position, results of operations or cash flows as credit losses were not expected to be significant. The Company will continue to monitor the impact of the COVID-19 pandemic on expected credit losses.

Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2020

Basis of Presentation and Principles of Consolidation

The accompanying unaudited condensed consolidated interim financial statements include the accounts of Grubhub Inc. and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and in accordance with the rules and regulations of the United States Securities and Exchange Commission (the “SEC”). Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. These unaudited condensed consolidated interim financial statements include all wholly-owned subsidiaries and reflect all normal and recurring adjustments, as well as any other than normal adjustments, that are, in the opinion of management, necessary for a fair presentation of the results for the interim periods and should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2019 filed with the SEC on February 28, 2020 (the “2019 Form 10-K”). All significant intercompany transactions have been eliminated in consolidation. Operating results for the three and six months ended June 30, 2020 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2020.

Use of Estimates

The preparation of condensed consolidated financial statements in accordance with GAAP requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and the related disclosures at the date of the financial statements, as well as the reported amounts of revenue and expenses during the periods presented. These estimates, judgments and assumptions take into account historical and forward-looking factors that the Company believes are reasonable including, but not limited to, the potential impacts arising from the COVID-19 pandemic and measures implemented to prevent its spread. As the extent and duration of the impacts from the COVID-19 pandemic remain unclear, the Company’s estimates and assumptions may evolve as conditions change. Significant items subject to such estimates, judgments and assumptions include revenue recognition, website and internal-use software development costs, goodwill, valuation and recoverability of intangible assets with finite lives and other long-lived assets, stock-based compensation, and income taxes. Actual results could differ significantly from these estimates.

Changes in Accounting Principle and Recently Issued Accounting Pronouncements

Changes in Accounting Principle

See “Recently Issued Accounting Pronouncements” below for a description of accounting principle changes adopted during the six months ended June 30, 2020 related to credit losses. There have been no other material changes to the Company’s significant accounting policies described in the 2019 Form 10-K.

Recently Issued Accounting Pronouncements

In June 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2016-13, “Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). ASU 2016-13 introduces a new forward-looking approach, based on expected losses, to estimate credit losses on certain types of financial instruments, including trade receivables and held-to-maturity debt securities, which requires entities to incorporate considerations of historical information, current information and reasonable and supportable forecasts. This ASU also expands disclosure requirements. ASU 2016-13 was effective for and adopted by the Company in the first quarter of 2020. The guidance was applied using the modified-retrospective approach. The adoption of ASU 2016-13 did not have a material impact on the Company’s consolidated financial position, results of operations or cash flows as credit losses were not expected to be significant. The Company will continue to monitor the impact of the COVID-19 pandemic on expected credit losses.