Earnings per Share - Additional Information (Detail)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Stock options outstanding but excluded from the computation of diluted earnings per share	131,273	1,142,840	1,210,970
Unvested restricted stock excluded from calculation of basic earnings per share	54,124	59,196	20,630

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

Nonvested equity-based payment awards that contain forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) that result in incremental common shares.

+ References

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+ Details