Property and Equipment - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 24, 2014	Sep. 30, 2015	Sep. 24, 2014	Dec. 31, 2014
Property Plant And Equipment [Abstract]
Depreciation expense	$ 3,300,000	$ 2,900,000	$ 9,600,000	$ 8,300,000
Gross value of assets under capital leases for buildings and improvements	1,559,200		1,559,200		$ 1,800,800
Accumulated depreciation of assets under capital leases	1,461,000		1,461,000		$ 1,673,000
Capital expenditures	10,800,000		21,100,000
Capital expenditures for restaurant remodeling	1,700,000		5,900,000
Capital expenditures for new restaurants	$ 6,900,000		$ 10,600,000