This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

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-Publisher FASB

-Name Accounting Standards Codification

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-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 7, 8, 9, 10

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The portion of the carrying value of long-term convertible debt as of the balance sheet date that is scheduled to be repaid within one year or in the normal operating cycle if longer. Convertible debt is a financial instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

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- Definition

Interest rate stated in the contractual debt agreement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Sum of the carrying values as of the balance sheet date of all long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year (current maturities) or the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

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- Definition

Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, and (3) securities available-for-sale which are intended to be held for less than one year or the normal operating cycle, whichever is longer.

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Fair Value of Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2011	Dec. 31, 2010	Feb. 29, 2004
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Marketable securities, current	$ 79,146	$ 193,279
Liabilities	23,653	96,692
Liabilities	513,386	17,759
Fair Value Measurements Nonrecurring \| Carrying Value
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Cash and cash equivalents	2,238,769	2,091,203
Marketable securities, current	20,992	52,087
Notes receivable, including noncurrent portion	43,512	44,789
Fair Value Measurements Nonrecurring \| Carrying Value \| 3.375% Senior Notes due September 15, 2021
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Liabilities	495,614
Fair Value Measurements Nonrecurring \| Carrying Value \| 1.5% Convertible Senior Notes due February 15, 2024
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Liabilities	23,653	96,692
Fair Value Measurements Nonrecurring \| Carrying Value \| 5.625% Municipal Bonds
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Liabilities	17,772	17,759
Fair Value Measurements Nonrecurring \| Fair Value
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Cash and cash equivalents	2,238,769	2,091,203
Marketable securities, current	20,992	52,087
Notes receivable, including noncurrent portion	43,512	44,789
Fair Value Measurements Nonrecurring \| Fair Value \| 3.375% Senior Notes due September 15, 2021
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Liabilities	502,175
Fair Value Measurements Nonrecurring \| Fair Value \| 1.5% Convertible Senior Notes due February 15, 2024
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Liabilities	52,068	230,214
Fair Value Measurements Nonrecurring \| Fair Value \| 5.625% Municipal Bonds
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Liabilities	$ 17,899	$ 18,039
3.375% Senior Notes due September 15, 2021
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Debt instrument interest rate (as a percent)	3.375%
1.5% Convertible Senior Notes due February 15, 2024
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Debt instrument interest rate (as a percent)	1.50%	1.50%	1.50%
5.625% Municipal Bonds
Estimated fair values of the company's financial instruments that are not measured at fair value on a recurring basis
Debt instrument interest rate (as a percent)	5.625%	5.625%