Net Income Per Share - Schedule of Reconciliation of Basic and Diluted Share Counts (Detail) - shares	3 Months Ended	6 Months Ended
Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Earnings Per Share [Abstract]
Weighted-average shares outstanding—basic (shares)	38,482,074	38,449,240	38,473,641	38,443,130
Dilutive effect of stock options and restricted shares (shares)	561,360	674,721	541,618	659,371
Weighted-average shares outstanding— diluted (shares)	39,043,434	39,123,961	39,015,259	39,102,501

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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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-Publisher FASB
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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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