Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended		9 Months Ended							0 Months Ended
	Sep. 30, 2014 item	Dec. 31, 2013	Sep. 30, 2014 Irving lease item	Sep. 30, 2014 Louisville lease item	Sep. 30, 2014 Everett, Massachusetts item	Sep. 30, 2014 Longmont, Colorado item	Sep. 30, 2014 Montgomeryville, Pennsylvania item	Sep. 30, 2014 Fargo, North Dakota item	Sep. 30, 2014 Logan, Utah item	Dec. 31, 2013 Aspen Creek concept restaurant	Dec. 31, 2013 Aspen Creek concept restaurant
Commitments and Contingencies
Estimated cost to complete capital project commitments (in dollars)	$ 114.0	$ 65.2
Real estate lease agreements
Number of restaurants sold										2	2
Number of lease renewal terms			3	3	3	3	3	3	3
Lease renewal term			5 years	5 years	5 years	5 years	5 years	5 years	5 years
Number of franchises with real estate lease agreements	5
Ownership percentage					5.00%	5.00%		5.00%
Amount of liability recorded for guarantees	$ 0
Number of suppliers providing most of the company's beef	4
Minimum age specified in age discrimination allegation against entity	40 years