Commitments and Contingencies - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 27, 2017 USD ($) lawsuit agreement lease
Other Commitments [Line Items]
Date of class action filed in court	On or about February 24, 2014
Number of lawsuits consolidated | lawsuit	2
Officers
Other Commitments [Line Items]
Number of at-will employment agreements | agreement	4
Property Lease Guarantee
Other Commitments [Line Items]
Number of leases assigned to franchisees | lease	5
Latest lease expiration year	2036
Contingent lease obligations, maximum exposure	$ 2.9
Contingent lease obligations, maximum exposure, if discounted at estimated pre-tax cost of debt	2.5
Chicken
Other Commitments [Line Items]
Purchase commitments, estimated obligations	$ 11.3