Long-Term Debt (Schedule Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Nov. 21, 2013
Debt Instrument [Line Items]
8.25% Senior subordinated notes due September 2018	$ 179,442	$ 200,000
1.00% Convertible senior notes due December 2020	220,950	216,635	215,800
Revolving credit facility, including swing-line credit facility	73,220	72,547
Equipment financing notes	616	1,332
Total	474,228	490,514
Less: current portion	615	1,289
Total long-term debt, excluding current portion	473,613	489,225
Weighted-average combined rate	2.20%	2.50%
Senior subordinated notes due September 2018 [Member]
Debt Instrument [Line Items]
Notes stated interest percentage	8.25%
Convertible senior notes due December 2020 [Member]
Debt Instrument [Line Items]
1.00% Convertible senior notes due December 2020	$ 220,950	$ 216,635
Notes stated interest percentage	1.00%

Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

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Amount borrowed under the credit facility as of the balance sheet date.

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The effective interest rate at the end of the reporting period.

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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