Consolidated Statement of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance (in shares) at Dec. 28, 2013		54,901
Balance at Dec. 28, 2013	$ 225,220	$ 549	$ 5,382	$ 219,276	$ 13
Comprehensive income:
Net income	67,974	0	0	67,974	0
Unrealized gain (loss) on available-for-sale marketable debt securities	(47)	$ 0	0	0	(47)
Exercise of common stock options (in shares)		239
Exercise of common stock options	2,873	$ 2	2,871	0	0
Tax effect from stock-based compensation	581	$ 0	581	0	0
Stock-based compensation (in shares)		(96)
Stock-based compensation	6,798	$ (1)	6,799	0	0
Repurchases of common stock (in shares)		(2,246)
Repurchases of common stock	(46,492)	$ (22)	(15,633)	(30,837)	0
Balance (in shares) at Jan. 03, 2015		52,798
Balance at Jan. 03, 2015	256,907	$ 528	0	256,413	(34)
Comprehensive income:
Net income	50,519	0	0	50,519	0
Unrealized gain (loss) on available-for-sale marketable debt securities	20	$ 0	0	0	20
Exercise of common stock options (in shares)		253
Exercise of common stock options	2,976	$ 3	2,973	0	0
Tax effect from stock-based compensation	1,828	$ 0	1,828	0	0
Stock-based compensation (in shares)		(7)
Stock-based compensation	10,290	$ 0	10,290	0	0
Repurchases of common stock (in shares)		(3,642)
Repurchases of common stock	$ (100,201)	$ (37)	(15,091)	(85,073)	0
Balance (in shares) at Jan. 02, 2016	49,402	49,402
Balance at Jan. 02, 2016	$ 222,339	$ 494	0	221,859	(14)
Comprehensive income:
Net income	51,417	0	0	51,417	0
Unrealized gain (loss) on available-for-sale marketable debt securities	14	$ 0	0	0	14
Exercise of common stock options (in shares)		188
Exercise of common stock options	2,298	$ 2	2,296	0	0
Tax effect from stock-based compensation	(1,016)	$ 0	(1,016)	0	0
Stock-based compensation (in shares)		11
Stock-based compensation	11,961	$ 0	11,961	0	0
Repurchases of common stock (in shares)		(6,032)
Repurchases of common stock	$ (126,693)	$ (60)	(13,241)	(113,392)	0
Balance (in shares) at Dec. 31, 2016	43,569	43,569
Balance at Dec. 31, 2016	$ 160,320	$ 436	$ 0	$ 159,884	$ 0