Earnings Per Share (Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Earnings Per Share [Abstract]
Net income	$ 21,245	$ 16,293
Weighted average common shares outstanding	72,854,000	72,704,000
Dilutive effect of stock-based awards	536,000	434,000
Shares used in computing diluted earnings per share	73,390,000	73,138,000
Basic earnings per share	$ 0.29	$ 0.22
Diluted earnings per share	$ 0.29	$ 0.22
Number of antidilutive options that were excluded from computation of earnings per share	0	0

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Antidilution

-URI http://asc.fasb.org/extlink&oid=6505113

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Publisher FASB

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-Glossary Diluted Earnings Per Share

-URI http://asc.fasb.org/extlink&oid=6510752

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-Publisher FASB

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-Glossary Contingent Stock Agreement

-URI http://asc.fasb.org/extlink&oid=6508534

+ Details

- Definition

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

+ References

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-Topic 260

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-Paragraph 2

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+ Details

- Definition

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.

+ References+ Details

- Definition

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

+ References

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-Appendix A

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-Glossary Other Comprehensive Income

-URI http://asc.fasb.org/extlink&oid=6519514

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Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Glossary Net Income

-URI http://asc.fasb.org/extlink&oid=6518256

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+ Details

- Definition

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.

+ References+ Details

- Definition

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

+ References

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-Glossary Weighted-Average Number of Common Shares Outstanding

-URI http://asc.fasb.org/extlink&oid=6528421

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+ Details