Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2018	Sep. 27, 2017	Sep. 26, 2018	Sep. 27, 2017
Earnings Per Share [Abstract]
Net income	$ 10,805	$ 9,325	$ 32,190	$ 26,447
Weighted average shares outstanding - basic (in shares)	63,246	66,873	63,774	69,095
Effect of dilutive share-based compensation awards	2,276	2,337	2,348	2,282
Weighted average shares outstanding - diluted (in shares)	65,522	69,210	66,122	71,377
Basic net income per share	$ 0.17	$ 0.14	$ 0.50	$ 0.38
Diluted net income per share	$ 0.16	$ 0.13	$ 0.49	$ 0.37
Antidilutive share-based compensation awards (in shares)	0	606	471	606