Earnings Per Share (Details)	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Earnings Per Share [Abstract]
Weighted-average common shares outstanding - basic	48,008,998	47,944,193	47,934,810	46,155,846
Dilutive effect of Equity-based Incentive Awards	0	994,573	0	1,052,259
Weighted-average common shares outstanding - diluted	48,008,998	48,938,766	47,934,810	47,208,105
Anti-dilutive Equity-based Incentive Awards excluded from the computation of diluted income per share	958,727	54,260	960,622	34,260

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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+ 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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+ Details