Earnings Per Share (Computation Of Basic And Diluted Income Per Common 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 Share
Net income	$ 39,368	$ 38,030	$ 76,785	$ 57,224
Basic common shares outstanding	100,094	102,035	100,416	101,982
Stock options	293	233	314	248
Unvested restricted stock	741	618	788	655
Dilutive common shares outstanding	101,128	102,886	101,518	102,885
Basic income per common share	$ 0.39	$ 0.37	$ 0.76	$ 0.56
Diluted income per common share	$ 0.39	$ 0.37	$ 0.76	$ 0.56

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of stock option awards using the treasury stock method.

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

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The amount of net income or loss for the period per each share of common stock and dilutive common stock equivalents outstanding during the reporting period.

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This element represents nonvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid). Basic and dilutive earnings per share are generally disclosed for such shares using the two-class method.

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The portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes.

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The average number of shares issued and outstanding that are used in calculating diluted EPS, determined based on the timing of issuance of shares in the period.

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Number of [basic] shares, after adjustment for contingently issuable shares and other shares not deemed outstanding, determined by relating the portion of time within a reporting period that common shares have been outstanding to the total time in that period.

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