Net Income Per Share - Computation of Basic and Diluted Net Income per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 23, 2020	Sep. 25, 2019	Sep. 23, 2020	Sep. 25, 2019
Numerator:
Net income	$ 9,920	$ 6,402	$ 19,019	$ 21,402
Denominator:
Weighted-average shares outstanding-Basic (shares)	35,471,452	35,859,502	34,989,007	37,484,372
Weighted-average shares outstanding-Diluted (shares)	36,064,559	36,397,368	35,609,320	38,173,097
Net income per share-Basic (usd per share)	$ 0.28	$ 0.18	$ 0.54	$ 0.57
Net income per share-Diluted (usd per share)	$ 0.28	$ 0.18	$ 0.53	$ 0.56
Anti-dilutive securities not considered in diluted EPS calculation (shares)	4,071	882,253	129,218	636,099