Fair Value of Financial Instruments	6 Months Ended
Fair Value of Financial Instruments	Jun. 30, 2015
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments	3. Fair Value of Financial Instruments The carrying value of the Company’s cash and cash equivalents, accounts receivable and accounts payable approximate fair value because of their short-term nature. Investments, all of which are classified as held-to-maturity, are carried at amortized cost, which approximates fair value. Investments consist of U.S. treasury notes and CDARS, certificates of deposit placed through an account registry service, with maturities up to approximately two years. Fair market value of U.S. treasury notes is measured using level 1 inputs (quoted prices for identical assets in active markets) and fair market value of CDARS is measured based on level 2 inputs (quoted prices for identical assets in markets that are not active). The Company also maintains 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 and carried at fair value, and are included in other assets in the consolidated balance sheet. Fair market value of mutual funds is measured using level 1 inputs (quoted prices for identical assets in active markets). The fair value of the investments in the rabbi trust was $18,624 and $16,147 as of June 30, 2015 and December 31, 2014, respectively. The Company records trading gains and losses in general and administrative expenses in the consolidated statement of income, along with the offsetting amount related to the increase or decrease in deferred compensation to reflect its exposure to liabilities for payment under the deferred plan. For the three and six months ended June 30, 2015, the Company recorded $116 and $256, respectively, of unrealized gains on investments held in the rabbi trust. For the three and six months ended June 30, 2014, the company recorded $292 and $436, respectively, of unrealized gains on investments held in the rabbi trust.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.