Consolidated Statement of Shareholders' Equity - 3 months ended Mar. 31, 2018 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]
Balance (in shares) at Dec. 30, 2017	38,813,000	38,813,000
Balance at Dec. 30, 2017	$ 89,156	$ 388	$ 0	$ 88,768
Net income	20,548			20,548
Exercise of common stock options (in shares)		68,000
Exercise of common stock options	857	$ 1	856	0
Stock-based compensation (in shares)		211,000
Stock-based compensation	3,084	$ 2	3,082	0
Repurchases of common stock (in shares)		(2,149,000)
Repurchases of common stock	$ (77,648)	$ (22)	(3,938)	(73,688)
Balance (in shares) at Mar. 31, 2018	36,943,000	36,943,000
Balance at Mar. 31, 2018	$ 35,997	$ 369	$ 0	$ 35,628