Condensed 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, 2021	$ 361,498	$ 66	$ 265,328	$ (1,932)	$ 421,809	$ (323,773)
Balances (in shares) at Jan. 01, 2021		65,707				13,903
Employee stock purchase plan	543		485			$ 58
Employee stock purchase plan (in shares)						(6)
Amortization of unrecognized stock-based compensation	3,738		3,738
Foreign currency translation adjustments	243			243
Grant of restricted stock units to settle accrued bonus	7,637		7,637
Settlement of restricted stock units	(15,634)		(3,176)		(1,679)	$ (10,779)
Settlement of restricted stock units (in shares)						(313)
Unrealized gain on investments	(4)			(4)
Dividends and dividend equivalent rights	(11,261)				(11,261)
Net income	30,848				30,848
Balance at Apr. 02, 2021	377,608	$ 66	274,012	(1,693)	439,717	$ (334,494)
Balances (in shares) at Apr. 02, 2021		65,707				13,584
Balance at Dec. 31, 2021	417,065	$ 66	281,419	(1,983)	478,370	$ (340,807)
Balances (in shares) at Dec. 31, 2021		65,707				13,591
Employee stock purchase plan	564		511			$ 53
Employee stock purchase plan (in shares)						(6)
Amortization of unrecognized stock-based compensation	4,094		4,094
Purchase of treasury stock	(48,554)					$ (48,554)
Purchase of treasury stock (in shares)						553
Foreign currency translation adjustments	(310)			(310)
Grant of restricted stock units to settle accrued bonus	10,200		10,200
Settlement of restricted stock units	(12,904)		(2,335)		(1,392)	$ (9,177)
Settlement of restricted stock units (in shares)						(253)
Dividends and dividend equivalent rights	(13,200)				(13,200)
Net income	29,609				29,609
Balance at Apr. 01, 2022	$ 386,564	$ 66	$ 293,889	$ (2,293)	$ 493,387	$ (398,485)
Balances (in shares) at Apr. 01, 2022		65,707				13,885