Income Taxes (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012	Dec. 29, 2012	Dec. 31, 2011
Entity Location [Line Items]
Cash and cash equivalents	$ 16,702,000	$ 8,800,000	$ 16,702,000	$ 8,800,000	$ 9,276,000	$ 20,841,000
Gross unrecognized tax benefits	6,500,000		6,500,000		6,000,000
Interest and penalties related to unrecognized tax benefits in noncurrent liabilities	2,500,000		2,500,000		2,300,000
Amount, if recognized, that affects the effective tax rate	7,300,000		7,300,000
Potential reduction in unrecognized tax benefit	3,000,000		3,000,000
Effective Income Tax Rate, Continuing Operations	38.00%	39.40%	37.60%	40.30%
Canada [Member]
Entity Location [Line Items]
Cash and cash equivalents	$ 10,600,000		$ 10,600,000		$ 8,200,000