Property and Equipment - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 01, 2015	Jun. 25, 2014	Jul. 01, 2015	Jun. 25, 2014	Dec. 31, 2014
Property Plant And Equipment [Abstract]
Depreciation expense	$ 3,200,000	$ 2,800,000	$ 6,300,000	$ 5,300,000
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	1,451,000		1,451,000		$ 1,673,000
Capital expenditures	6,500,000		8,900,000
Capital expenditures for restaurant remodeling	2,300,000		3,500,000
Capital expenditures for new restaurants	$ 2,900,000		$ 3,100,000