Marketable Securities Auction Rate (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended					0 Months Ended	3 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013	Dec. 28, 2013	Jun. 28, 2014 Total Auction Rate Securities	Dec. 28, 2013 Total Auction Rate Securities	Jun. 19, 2014 Federally-insured or FFELP guaranteed student loan auction rate securities	Jun. 28, 2014 Federally-insured or FFELP guaranteed student loan auction rate securities	Jun. 19, 2014 Federally-insured or FFELP guaranteed student loan auction rate securities	Dec. 28, 2013 Federally-insured or FFELP guaranteed student loan auction rate securities
Schedule of Available-for-sale Securities [Line Items]
Par value						$ 0	$ 5,700		$ 0	$ 5,700	$ 5,700
Available-for-sale securities	109,061		109,061		106,746	0	5,241		0	5,200	5,241
Proceeds from sales of auction rate securities			5,488	0				5,500
Available-for-sale securities, gross realized gain	(1,147)	0	(1,147)	0					1,700
Realized gain on sale of auction rate securities, previously unrealized, net of tax			$ (1,147)						$ 1,100