Derivatives (Gain (Loss) on Derivatives) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 28, 2014		Jun. 29, 2013		Jun. 28, 2014		Jun. 29, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion)	$ 1,029	[1]	$ 1,353	[1]	$ (118)	[2]	$ 3,128	[2]
Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	32	[3]	1,110	[3]	1,681	[3]	1,095	[3]
Gain or (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	351	[4]	(295)	[4]	726	[4]	(42)	[4]
Loss activity recognized in other comprehensive loss	1,000		(1,400)		(100)		(3,100)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(400)		(500)		100		(1,200)
Corn Option [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss activity recognized in other comprehensive loss	1,046		1,450		(273)		3,041
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	405		562		(107)		1,178
Corn Option [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion)	1,046	[1]	1,450	[1]	(273)	[2]	3,041	[2]
Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	32	[3]	866	[3]	1,324	[3]	908	[3]
Gain or (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	355	[4]	(288)	[4]	731	[4]	(34)	[4]
Natural Gas Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss activity recognized in other comprehensive loss	(17)		(97)		155		87
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(6)		(38)		61		33
Natural Gas Swap [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion)	(17)	[1]	(97)	[1]	155	[2]	87	[2]
Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	0	[3]	244	[3]	357	[3]	187	[3]
Gain or (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$ (4)	[4]	$ (7)	[4]	$ (5)	[4]	$ (8)	[4]

[1] Amount recognized in accumulated OCI (effective portion) is reported as accumulated other comprehensive income/ (loss) of approximately $1.0 million and approximately $1.4 million recorded net of taxes of approximately $0.4 million and less than $0.5 million as of June 28, 2014 and June 29, 2013, respectively.

[2] Amount recognized in accumulated OCI (effective portion) is reported as accumulated other comprehensive income/ (loss) of approximately $(0.1) million and approximately $3.1 million recorded net of taxes of approximately less than $(0.1) million and $1.2 million as of June 28, 2014 and June 29, 2013, respectively.

[3] Gains and (losses) reclassified from accumulated OCI into income (effective portion) for corn options and natural gas swaps are included in cost of sales, respectively, in the Company’s consolidated statements of operations.

[4] Gains and (losses) recognized in income on derivatives (ineffective portion) for corn options and natural gas swaps is included in other income/ (expense), net in the Company’s consolidated statements of operations.