Net Fair Value of Commodity Price Risk (Detail) - USD ($) $ in Thousands	Apr. 22, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Assets	$ 541	$ 1,611
Liabilities	(6,926)	(2,435)
Net Fair Value	(6,385)	(824)
Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Assets	541	1,611
Liabilities	(6,926)	(2,435)
Net Fair Value	(6,385)	(824)
Other Current Assets
Derivative Instruments, Gain (Loss) [Line Items]
Assets	517	1,576
Other Current Assets | Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Assets	517	1,576
Other LongTerm Assets
Derivative Instruments, Gain (Loss) [Line Items]
Assets	24	35
Other LongTerm Assets | Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Assets	24	35
Other Current Liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liabilities	(6,488)	(2,435)
Other Current Liabilities | Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Liabilities	(6,488)	$ (2,435)
Other LongTerm Liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liabilities	(438)
Other LongTerm Liabilities | Level 1
Derivative Instruments, Gain (Loss) [Line Items]
Liabilities	$ (438)