Property and Equipment - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2016	Jul. 01, 2015	Jun. 29, 2016	Jul. 01, 2015	Dec. 30, 2015
Property Plant And Equipment [Abstract]
Depreciation expense	$ 4.0	$ 3.2	$ 7.7	$ 6.3
Gross value of assets under capital leases for buildings and improvements	1.6		1.6		$ 1.6
Accumulated depreciation of assets under capital leases	1.5		1.5		$ 1.5
Capital expenditures	8.4		14.3
Capital expenditures for restaurant remodeling	0.1		1.6
Capital expenditures for new restaurants	$ 6.3		$ 9.2