Earnings per Share (Schedule of Earnings per Share, Basic and Diluted) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Earnings Per Share [Abstract]
Weighted average common shares outstanding, used in computing basic earnings per share	33,840	33,808	33,725
Effect of dilutive stock options and restricted stock units	292	396	367
Weighted-average common shares outstanding, used in computing diluted earnings per share	34,132	34,204	34,092
Basic	$ 2.95	$ 3.06	$ 2.28
Diluted	$ 2.93	$ 3.03	$ 2.26

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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+ 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 sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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- 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.

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- 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

+ Details