Derivatives (Gain (Loss) on Derivatives) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 27, 2014		Sep. 28, 2013		Sep. 27, 2014		Sep. 28, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion)	$ 2,543	[1]	$ 2,662	[1]	$ 2,425	[2]	$ 5,790	[2]
Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	1,282	[3]	2,060	[3]	2,963	[3]	3,155	[3]
Gain or (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	26	[4]	216	[4]	752	[4]	257	[4]
Loss activity recognized in other comprehensive loss	2,500		(2,700)		2,400		(5,800)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(1,000)		(1,000)		(900)		(2,200)
Corn Option [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss activity recognized in other comprehensive loss	2,538		2,676		2,265		5,717
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	985		1,031		878		2,209
Corn Option [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion)	2,538	[1]	2,676	[1]	2,265	[2]	5,717	[2]
Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	1,212	[3]	2,155	[3]	2,536	[3]	3,063	[3]
Gain or (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	22	[4]	215	[4]	753	[4]	249	[4]
Natural Gas Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Loss activity recognized in other comprehensive loss	5		(14)		160		73
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	2		(5)		63		28
Natural Gas Swap [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (Loss) Recognized in OCI on Derivatives (Effective Portion)	5	[1]	(14)	[1]	160	[2]	73	[2]
Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	70	[3]	(95)	[3]	427	[3]	92	[3]
Gain or (Loss) Recognized in Income on Derivatives (Ineffective Portion and Amount Excluded from Effectiveness Testing)	$ 4	[4]	$ 1	[4]	$ (1)	[4]	$ 8	[4]

[1] Amount recognized in accumulated OCI (effective portion) is reported as accumulated other comprehensive income/ (loss) of approximately $2.5 million and approximately $2.7 million recorded net of taxes of approximately $1.0 million and $1.0 million as of September 27, 2014 and September 28, 2013, respectively.

[2] Amount recognized in accumulated OCI (effective portion) is reported as accumulated other comprehensive income/ (loss) of approximately $2.4 million and approximately $5.8 million recorded net of taxes of approximately less than $0.9 million and $2.2 million as of September 27, 2014 and September 28, 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.