Net Fair Value of Commodity Price Risk (Detail) - USD ($) $ in Thousands	Apr. 21, 2018	Dec. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Assets	$ 4,634	$ 291
Liabilities	(1,073)	(10,886)
Net Fair Value	3,561	(10,595)
Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Assets	4,634	291
Liabilities	(1,073)	(10,886)
Net Fair Value	3,561	(10,595)
Other Current Assets
Derivative Instruments, Gain (Loss) [Line Items]
Assets	4,071	259
Other Current Assets | Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Assets	4,071	259
Other LongTerm Assets
Derivative Instruments, Gain (Loss) [Line Items]
Assets	563	32
Liabilities		(639)
Other LongTerm Assets | Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Assets	563	32
Liabilities		(639)
Other Current Liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liabilities	(689)	(10,247)
Other Current Liabilities | Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Liabilities	(689)	$ (10,247)
Other LongTerm Liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liabilities	(384)
Other LongTerm Liabilities | Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Liabilities	$ (384)