Income Taxes	9 Months Ended
Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 5 Income taxes Prior to the Separation, Cars.com LLC was a multi-member LLC that is considered to be a partnership for U.S. income tax purposes. Multi-member LLCs are generally considered flow-through entities and therefore not subject to federal, state, or local income taxes. Effective with the Separation, the Company established a corporate legal entity structure that is subject to U.S. corporate income tax on a stand-alone basis post-Separation. Income tax expense was $13.0 million for the three months ended September 30, 2017, compared to income tax expense of $0.5 million for the same period of the prior year. The prior year income tax expense represents only two months of DealerRater activity as DealerRater was acquired on August 1, 2016. The effective income tax rate, expressed by calculating the income tax expense as a percentage of income before income taxes, was 38.3% for the three months ended September 30, 2017 and differed from the U.S. federal statutory rate primarily due to state income taxes. Income tax expense was $15.8 million for the nine months ended September 30, 2017, based upon four months of Cars.com, LLC information and nine months of DealerRater information, compared to income tax expense of $0.5 million for the same period of the prior year. The prior year income tax expense represents only two months of DealerRater activity as DealerRater was acquired on August 1, 2016. The effective income tax rate, expressed by calculating the income tax expense as a percentage of income before income taxes, was 17.8% for the nine months ended September 30, 2017 and differed from the U.S. federal statutory rate primarily due to pre-Separation income generated by a flow-through entity not subject to federal, state or local income taxes. With the implementation of the post-Separation legal entity structure, the Company was required to record deferred tax assets and liabilities for temporary differences between financial accounting and tax reporting. Accordingly, the Company recorded $267 million of net deferred tax liability associated with the outside basis difference in the Cars.com, LLC flow-through entity with the offset recorded in TEGNA’s investment net. Separately, the Company recorded $8 million of net deferred tax asset associated with the DealerRater corporate entity during 2017. To achieve a tax qualified Employee Share Purchase Program (“ESPP”), participating employees of Cars.com, LLC must be employed by an entity taxed as a C corporation. Consequently, in October 2017, Cars.com, LLC prospectively changed its corporate structure to convert from being taxed as a partnership to being taxed as a C corporation. As a result of the change in corporate structure, Cars.com, LLC was also required to change its reporting of deferred tax assets and liabilities. This reporting change results in a $69 million non-cash write-off of the deferred tax liability associated with non-deductible goodwill which Cars.com, LLC will record through a credit to income tax expense in the fourth quarter of 2017.

NOTE 5

Income taxes

Prior to the Separation, Cars.com LLC was a multi-member LLC that is considered to be a partnership for U.S. income tax purposes. Multi-member LLCs are generally considered flow-through entities and therefore not subject to federal, state, or local income taxes. Effective with the Separation, the Company established a corporate legal entity structure that is subject to U.S. corporate income tax on a stand-alone basis post-Separation. Income tax expense was $13.0 million for the three months ended September 30, 2017, compared to income tax expense of $0.5 million for the same period of the prior year. The prior year income tax expense represents only two months of DealerRater activity as DealerRater was acquired on August 1, 2016. The effective income tax rate, expressed by calculating the income tax expense as a percentage of income before income taxes, was 38.3% for the three months ended September 30, 2017 and differed from the U.S. federal statutory rate primarily due to state income taxes.

Income tax expense was $15.8 million for the nine months ended September 30, 2017, based upon four months of Cars.com, LLC information and nine months of DealerRater information, compared to income tax expense of $0.5 million for the same period of the prior year. The prior year income tax expense represents only two months of DealerRater activity as DealerRater was acquired on August 1, 2016. The effective income tax rate, expressed by calculating the income tax expense as a percentage of income before income taxes, was 17.8% for the nine months ended September 30, 2017 and differed from the U.S. federal statutory rate primarily due to pre-Separation income generated by a flow-through entity not subject to federal, state or local income taxes.

With the implementation of the post-Separation legal entity structure, the Company was required to record deferred tax assets and liabilities for temporary differences between financial accounting and tax reporting. Accordingly, the Company recorded $267 million of net deferred tax liability associated with the outside basis difference in the Cars.com, LLC flow-through entity with the offset recorded in TEGNA’s investment net. Separately, the Company recorded $8 million of net deferred tax asset associated with the DealerRater corporate entity during 2017.

To achieve a tax qualified Employee Share Purchase Program (“ESPP”), participating employees of Cars.com, LLC must be employed by an entity taxed as a C corporation. Consequently, in October 2017, Cars.com, LLC prospectively changed its corporate structure to convert from being taxed as a partnership to being taxed as a C corporation. As a result of the change in corporate structure, Cars.com, LLC was also required to change its reporting of deferred tax assets and liabilities. This reporting change results in a $69 million non-cash write-off of the deferred tax liability associated with non-deductible goodwill which Cars.com, LLC will record through a credit to income tax expense in the fourth quarter of 2017.