Acquisition (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 28, 2014	Sep. 29, 2013	Sep. 30, 2012 May 30, 2012 Acquisition [Member]	Sep. 28, 2014 April 30, 2014 Acquisition [Member]	Sep. 28, 2014 June 30, 2014 Acquisition [Member]	Sep. 28, 2014 July 22, 2014 Acquisition [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition				Apr. 30, 2014	Jun. 30, 2014	Jul. 22, 2014
Number of Restaurants Acquired			278	4	4	21
Acquisition of restaurants, net of cash acquired	$ 13,021	$ 0		$ 700	$ 3,800	$ 8,500