Fair Value of Financial Instruments	3 Months Ended
Mar. 31, 2012
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments	7. Fair Value of Financial Instruments The Corporation’s financial instruments include cash and cash equivalents, marketable securities, short-term receivables and payables, and debt. Included in cash and cash equivalents are money market funds which are valued based on the published net asset value (“NAV”). Financial instruments also include an interest rate swap agreement, which is discussed further in Note 9 below. The carrying amounts of the Corporation’s financial instruments generally approximated their fair values at March 31, 2012 and December 31, 2011, except that, based on the borrowing rates available to the Corporation under current market conditions, the fair value of long-term debt (including current maturities) using Level 2 fair value inputs was approximately $610 million at March 31, 2012 and $601 million at December 31, 2011.

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.

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