Fair Value of Financial Instruments	9 Months Ended
Sep. 30, 2018
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments	4. Fair Value of Financial Instruments The carrying value of our cash and cash equivalents, accounts receivable and accounts payable approximate fair value because of their short-term nature. Our investments consist of U.S. treasury notes with maturities of up to one year. Fair value of investments is measured using Level 1 inputs (quoted prices for identical assets in active markets). We designate the appropriate classification of our investments at the time of purchase based upon the intended holding period. As of September 30, 2018, we transferred the classification of our investments from available-for-sale ("AFS") to held-to-maturity ("HTM") due to our ability and intent to hold these securities to maturity. The transfer from AFS to HTM was recorded at the fair value of the AFS securities at the time of transfer. The unrealized holding loss of $303, net of tax, at the date of transfer was retained in other comprehensive income (loss) on the condensed consolidated statement of other comprehensive income. Such amounts will be amortized to interest and other income on the condensed consolidated statement of income over the remaining life of the securities. The amortization of this unrealized holding loss will be offset by the discount created as a result of this reclassification, which will also be amortized over the remaining life of the securities to interest and other income on the condensed consolidated statement of income. HTM securities are carried at amortized cost, which approximated fair value as of September 30, 2018, and we recognize impairment charges when management believes the decline in the fair value of the investment is other-than-temporary. No impairment charges were recognized on our investments for the nine months ended September 30, 2018. We also maintain a rabbi trust to fund obligations under a deferred compensation plan. Amounts in the rabbi trust are invested in mutual funds, which are designated as trading securities carried at fair value, and are included in other assets on the condensed consolidated balance sheet. Fair value of mutual funds is measured using Level 1 inputs. The fair value of the investments in the rabbi trust was $16,926 and $19,887 as of September 30, 2018, and December 31, 2017, respectively. We record trading gains and losses in general and administrative expenses on the condensed consolidated statement of income, along with the offsetting amount related to the increase or decrease in deferred compensation to reflect our exposure to liabilities for payment under the deferred plan. Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis Assets recognized or disclosed at fair value on the consolidated financial statements on a nonrecurring basis include items such as leasehold improvements, property and equipment, goodwill, and other intangible assets. These assets are measured at fair value if determined to be impaired. Other than as disclosed in Note 5. “Corporate Restructuring Costs” and Note 6. “Restaurant Closure Costs and Impairment of Long-Lived Assets” as of September 30, 2018 and December 31, 2017, we had no non-financial assets or liabilities that were measured using Level 3 inputs.

4. Fair Value of Financial Instruments

The carrying value of our cash and cash equivalents, accounts receivable and accounts payable approximate fair value because of their short-term nature.

Our investments consist of U.S. treasury notes with maturities of up to one year. Fair value of investments is measured using Level 1 inputs (quoted prices for identical assets in active markets). We designate the appropriate classification of our investments at the time of purchase based upon the intended holding period.

As of September 30, 2018, we transferred the classification of our investments from available-for-sale ("AFS") to held-to-maturity ("HTM") due to our ability and intent to hold these securities to maturity. The transfer from AFS to HTM was recorded at the fair value of the AFS securities at the time of transfer. The unrealized holding loss of $303, net of tax, at the date of transfer was retained in other comprehensive income (loss) on the condensed consolidated statement of other comprehensive income. Such amounts will be amortized to interest and other income on the condensed consolidated statement of income over the remaining life of the securities. The amortization of this unrealized holding loss will be offset by the discount created as a result of this reclassification, which will also be amortized over the remaining life of the securities to interest and other income on the condensed consolidated statement of income.

HTM securities are carried at amortized cost, which approximated fair value as of September 30, 2018, and we recognize impairment charges when management believes the decline in the fair value of the investment is other-than-temporary. No impairment charges were recognized on our investments for the nine months ended September 30, 2018.

We also maintain a rabbi trust to fund obligations under a deferred compensation plan. Amounts in the rabbi trust are invested in mutual funds, which are designated as trading securities carried at fair value, and are included in other assets on the condensed consolidated balance sheet. Fair value of mutual funds is measured using Level 1 inputs. The fair value of the investments in the rabbi trust was $16,926 and $19,887 as of September 30, 2018, and December 31, 2017, respectively. We record trading gains and losses in general and administrative expenses on the condensed consolidated statement of income, along with the offsetting amount related to the increase or decrease in deferred compensation to reflect our exposure to liabilities for payment under the deferred plan.

Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis

Assets recognized or disclosed at fair value on the consolidated financial statements on a nonrecurring basis include items such as leasehold improvements, property and equipment, goodwill, and other intangible assets. These assets are measured at fair value if determined to be impaired.

Other than as disclosed in Note 5. “Corporate Restructuring Costs” and Note 6. “Restaurant Closure Costs and Impairment of Long-Lived Assets” as of September 30, 2018 and December 31, 2017, we had no non-financial assets or liabilities that were measured using Level 3 inputs.