Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 29, 2012	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Oct. 01, 2011	Jul. 02, 2011	Apr. 02, 2011	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Statement of Other Comprehensive Income [Abstract]
Net income	$ 12,495	$ 26,209	$ 16,973	$ 22,417	$ 15,370	$ 17,236	$ 11,289	$ 16,583	$ 78,094	$ 60,478	$ 31,568
Other comprehensive (loss) income – unrealized (loss) gain on available-for-sale marketable debt securities, net of income tax									(5)	25	0
Comprehensive income									$ 78,089	$ 60,503	$ 31,568