Earnings Per Share - Basic and Diluted Weighted Average Shares Outstanding Used to Compute Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share Basic And Diluted [Abstract]
Basic weighted average shares outstanding	37,049	36,950	37,046	36,952
Dilutive effect of stock options and restricted stock	861	912	825	922
Diluted weighted average shares outstanding	37,910	37,862	37,871	37,874

No definition available.

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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

+ References

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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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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.

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