Long-Term Debt (Components Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2011	Dec. 31, 2010
Debt Instrument [Line Items]
Total long-term debt	$ 306,611	$ 303,365
Less: Current maturities	3,960	3,960
Long-term debt less current maturities	302,651	299,405
Senior Convertible Debentures Due 2027, 2.75% [Member]
Debt Instrument [Line Items]
Principal amount of debt component	325,000	325,000
Less: Unamortized debt discount	(71,849)	(79,055)
Debt instrument interest rate stated percentage	2.75%
Debt instrument maturity year	2027
Carrying Amount Of Debt Component [Member]
Debt Instrument [Line Items]
Total long-term debt	253,151	245,945
Title XI Bonds Due 2025, 7.71% [Member]
Debt Instrument [Line Items]
Total long-term debt	$ 53,460	$ 57,420
Debt instrument interest rate stated percentage	7.71%
Debt instrument maturity year	2025

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- Definition

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

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- Definition

Interest rate stated in the contractual debt agreement.

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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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- Definition

The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

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- Definition

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date. May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

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- Definition

Total of the portions of the carrying amounts as of the balance sheet date of long-term debt, which may include notes payable, bonds payable, debentures, mortgage loans, and commercial paper, which are scheduled to be repaid within one year or the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

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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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