Other Comprehensive Income (Schedule of OCI) (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
Before-Tax Amount:
Amortization of prior service cost	$ 4	$ 15	$ 8	$ 30
Amortization of actuarial loss	520	1,300	1,039	2,600
Total defined benefit pension plans	524	1,315	1,047	2,630
Loss activity recognized in other comprehensive loss	1,000	(1,400)	(100)	(3,100)
Other Comprehensive income (loss)	(5,410)	1,558	12,932	4,663
Tax (Expense) or Benefit:
Amortization of prior service cost	(2)	(6)	(4)	(12)
Amortization of actuarial loss	(201)	(504)	(402)	(1,008)
Total defined benefit pension plans	(203)	(510)	(406)	(1,020)
Loss activity recognized in other comprehensive loss	400	500	(100)	1,200
Other Comprehensive income (loss)	(590)	(604)	292	(1,807)
Net-of-Tax Amount:
Amortization of prior service cost	2	9	4	18
Amortization of actuarial loss	319	796	637	1,592
Total defined benefit pension plans	321	805	641	1,610
Foreign currency translation	(6,931)	0	13,684	0
Net current-period other comprehensive income	(6,000)	954	13,224	2,856
Natural Gas Swap [Member]
Before-Tax Amount:
Loss reclassified to net income	0	(244)	(357)	(187)
Loss activity recognized in other comprehensive loss	(17)	(97)	155	87
Total swap derivatives	(17)	(341)	(202)	(100)
Tax (Expense) or Benefit:
Loss reclassified to net income	0	94	139	72
Loss activity recognized in other comprehensive loss	6	38	(61)	(33)
Total swap derivatives	6	132	78	39
Net-of-Tax Amount:
Loss reclassified to net income	0	(150)	(218)	(115)
Loss activity recognized in other comprehensive loss	(11)	(59)	94	54
Total swap derivatives	(11)	(209)	(124)	(61)
Corn Option [Member]
Before-Tax Amount:
Loss reclassified to net income	(32)	(866)	(1,324)	(908)
Loss activity recognized in other comprehensive loss	1,046	1,450	(273)	3,041
Total swap derivatives	1,014	584	(1,597)	2,133
Tax (Expense) or Benefit:
Loss reclassified to net income	12	336	513	352
Loss activity recognized in other comprehensive loss	(405)	(562)	107	(1,178)
Total swap derivatives	(393)	(226)	620	(826)
Net-of-Tax Amount:
Loss reclassified to net income	(20)	(530)	(811)	(556)
Loss activity recognized in other comprehensive loss	641	888	(166)	1,863
Total swap derivatives	621	358	(977)	1,307
Interest Rate Swap [Member]
Before-Tax Amount:
Foreign currency translation			13,684	0
Tax (Expense) or Benefit:
Foreign currency translation			0	0
Net-of-Tax Amount:
Foreign currency translation			13,684	0
Accumulated Other Comprehensive Income (Loss) [Member]
Before-Tax Amount:
Foreign currency translation	(6,931)	0
Tax (Expense) or Benefit:
Foreign currency translation	0	0
Net-of-Tax Amount:
Foreign currency translation	$ (6,931)	$ 0