Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive income (Loss) [Member]	Retained earnings [Member]	Treasury Stock [Member]
Balance at Jan. 01, 2016	$ 262,804	$ 66	$ 179,783	$ (1,805)	$ 269,259	$ (184,499)
Balance (in shares) at Jan. 01, 2016		65,707				14,266
Employee stock purchase plan	1,190	$ 0	883	0	0	$ 307
Employee stock purchase plan (in shares)						(46)
Exercise of stock options	566	0	161	0	0	$ 405
Exercise of stock options (in shares)						(60)
Amortization of unrecognized stock-based compensation	7,152	0	7,152	0	0	$ 0
Purchase of treasury shares	(24,456)	0	0	0	0	$ (24,456)
Purchase of treasury shares (in shares)						982
Foreign currency translation adjustments	(1,240)	0	0	(1,240)	0	$ 0
Grant of restricted stock units to settle accrued bonus	6,334	0	6,334	0	0	0
Settlement of restricted stock units	(7,685)	0	(701)	0	(5,791)	$ (1,193)
Settlement of restricted stock units (in shares)						(630)
Unrealized loss on investments	(81)	0	0	(81)	0	$ 0
Dividends and dividend equivalent rights	(18,773)	0	854	0	(19,627)	0
Other	55	0	133	0	(78)	0
Net income	47,480	0	0	0	47,480	0
Balance at Dec. 30, 2016	273,346	$ 66	194,599	(3,126)	291,243	$ (209,436)
Balance (in shares) at Dec. 30, 2016		65,707				14,512
Employee stock purchase plan	1,207	$ 0	847	0	0	$ 360
Employee stock purchase plan (in shares)						(40)
Exercise of stock options	818	0	144	0	0	$ 674
Exercise of stock options (in shares)						(69)
Amortization of unrecognized stock-based compensation	7,824	0	7,824	0	0	$ 0
Purchase of treasury shares	(11,931)	0	0	0	0	$ (11,931)
Purchase of treasury shares (in shares)						372
Foreign currency translation adjustments	1,187	0	0	1,187	0	$ 0
Grant of restricted stock units to settle accrued bonus	6,918	0	6,918	0	0	0
Settlement of restricted stock units	(9,520)	0	(1,017)	0	(5,667)	$ (2,836)
Settlement of restricted stock units (in shares)						(606)
Unrealized loss on investments	(90)	0	0	(90)	0	$ 0
Dividends and dividend equivalent rights	(21,976)	0	915	0	(22,891)	0
Net income	41,305	0	0	0	41,305	0
Balance at Dec. 29, 2017	289,088	$ 66	210,230	(2,029)	303,990	$ (223,169)
Balance (in shares) at Dec. 29, 2017		65,707				14,169
Employee stock purchase plan	1,474	$ 0	1,161	0	0	$ 313
Employee stock purchase plan (in shares)						(32)
Amortization of unrecognized stock-based compensation	8,550	0	8,550	0	0	$ 0
Purchase of treasury shares	(27,915)	0	0	0	0	$ (27,915)
Purchase of treasury shares (in shares)						562
Foreign currency translation adjustments	(1,015)	0	0	(1,015)	0	$ 0
Grant of restricted stock units to settle accrued bonus	7,643	0	7,643	0	0	0
Settlement of restricted stock units	(8,839)	0	(1,107)	0	(5,892)	$ (1,840)
Settlement of restricted stock units (in shares)						(491)
Unrealized loss on investments	191	0	0	191	0	$ 0
Dividends and dividend equivalent rights	(27,522)	0	806	0	(28,328)	0
Net income	72,254	0	0	0	72,254	0
Balance at Dec. 28, 2018	$ 313,909	$ 66	$ 227,283	$ (2,853)	$ 342,024	$ (252,611)
Balance (in shares) at Dec. 28, 2018		65,707				14,208