Marketable Securities Auction Rate (Details) (USD $)	12 Months Ended			0 Months Ended			3 Months Ended				0 Months Ended	3 Months Ended
	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011	May 22, 2012 Federally-insured or FFELP guaranteed student loan auction rate securities	Mar. 29, 2011 Federally-insured or FFELP guaranteed student loan auction rate securities	Jul. 29, 2010 Federally-insured or FFELP guaranteed student loan auction rate securities	Apr. 02, 2011 Federally-insured or FFELP guaranteed student loan auction rate securities	Oct. 02, 2010 Federally-insured or FFELP guaranteed student loan auction rate securities	Dec. 29, 2012 Federally-insured or FFELP guaranteed student loan auction rate securities	Dec. 31, 2011 Federally-insured or FFELP guaranteed student loan auction rate securities	Dec. 09, 2010 Auction market preferred shares issued by AMBAC Assurance Corporation	Jan. 01, 2011 Auction market preferred shares issued by AMBAC Assurance Corporation
Schedule of Available-for-sale Securities [Line Items]
Par Value				$ 2,600,000	$ 3,300,000	$ 3,800,000			$ 5,700,000	$ 8,300,000	$ 8,300,000
Fair Value				2,300,000	2,800,000	2,900,000			4,717,000	6,946,000	200,000
Sale proceeds from student loan auction rate securities sold at par				2,600,000	3,300,000
Sale proceeds from available-for-sale securities						3,300,000					500,000
Realized gain on sale of securities				400,000			600,000	400,000				300,000
Previously unrecognized gain relieved on sale of student loan auction rate securities	$ (78,000)	$ (133,000)	$ 0	$ 100,000			$ 100,000