Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 8,481	$ 9,926	$ 25,473	$ 33,397
Other comprehensive income (loss) – unrealized gain (loss) on available-for-sale marketable debt securities, net of income tax	20	(38)	30	(45)
Comprehensive income	$ 8,501	$ 9,888	$ 25,503	$ 33,352