Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 29, 2012 week item staff	Dec. 31, 2011 week	Jan. 01, 2011 week
Description of business
Number of U.S. office locations	11
Number of IT professionals, management and administrative staff employed	900
Fiscal year
Number of weeks in the fiscal year	52	52	52