Earnings Per Common Share (Summary Of Calculation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Earnings Per Common Share
Net income used for basic calculation	$ 34,745	$ 21,773	$ 61,575	$ 42,707
Interest expense and debt financing cost amortization, net of tax, related to our 1.375% convertible senior notes	4	11	16	52
Net income used for diluted calculation	$ 34,749	$ 21,784	$ 61,591	$ 42,759
Shares used in computing earnings per common share-basic	182,962	178,004	182,347	177,510
Shares issuable upon the assumed conversion of our 1.375% convertible senior notes	138	904	305	1,062
Stock awards	8,087	6,242	8,138	6,108
Dilutive potential common	8,225	7,146	8,443	7,170
Shares used in computing earnings per common share-diluted	191,187	185,150	190,790	184,680
Basic	$ 0.19	$ 0.12	$ 0.34	$ 0.24
Diluted	$ 0.18	$ 0.12	$ 0.32	$ 0.23

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The after-tax amount of interest recognized in the period associated with any convertible debt.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Net Income or Loss Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Shares issuable for little or no cash consideration upon the satisfaction of certain conditions (contingently issuable shares) are considered outstanding common shares and included in the computation of basic Earnings Per Share as of the date that all necessary conditions have been satisfied (in essence, when issuance of the shares is no longer contingent). Outstanding common shares that are contingently returnable (that is, subject to recall) are treated in the same manner as contingently issuable shares. Contingently issuable shares include shares that (a) will be issued in the future upon the satisfaction of specified conditions, (b) have been placed in escrow and all or part must be returned if specified conditions are not met, or (c) have been issued but the holder must return all or part if specified conditions are not met. The number of contingently issuable shares is determined by relating the portion of time within a reporting period that these shares have been outstanding to the total time in that period.

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