Guarantor Financial Information (Condensed Consolidating Statements of Comprehensive Income) (Loss) (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
Net income/ (loss)	$ 34,575	$ 26,418	$ (16,431)	$ 58,823
Other comprehensive income, net of tax:
Foreign currency translation	(6,931)	0	13,684	0
Pension adjustments	321	805	641	1,610
Total other comprehensive income/ (loss), net of tax	(6,000)	954	13,224	2,856
Total comprehensive income/ (loss)	28,575	27,372	(3,207)	61,679
Issuer [Member]
Net income/ (loss)	34,575	26,418	(16,431)	58,823
Other comprehensive income, net of tax:
Foreign currency translation	0		0
Pension adjustments	321	805	641	1,610
Total other comprehensive income/ (loss), net of tax	931	954	(460)	2,856
Total comprehensive income/ (loss)	35,506	27,372	(16,891)	61,679
Guarantors [Member]
Net income/ (loss)	50,670	26,927	85,300	57,362
Other comprehensive income, net of tax:
Foreign currency translation	0		0
Pension adjustments	0	0	0	0
Total other comprehensive income/ (loss), net of tax	0	0	0	0
Total comprehensive income/ (loss)	50,670	26,927	85,300	57,362
Non-guarantors [Member]
Net income/ (loss)	7,018	(1,160)	(16,251)	(1,877)
Other comprehensive income, net of tax:
Foreign currency translation	(6,931)		13,684
Pension adjustments	0	0	0	0
Total other comprehensive income/ (loss), net of tax	(6,931)	0	13,684	0
Total comprehensive income/ (loss)	87	(1,160)	(2,567)	(1,877)
Eliminations [Member]
Net income/ (loss)	(57,688)	(25,767)	(69,049)	(55,485)
Other comprehensive income, net of tax:
Foreign currency translation	0		0
Pension adjustments	0	0	0	0
Total other comprehensive income/ (loss), net of tax	0	0	0	0
Total comprehensive income/ (loss)	(57,688)	(25,767)	(69,049)	(55,485)
Natural Gas Swap [Member]
Other comprehensive income, net of tax:
Derivative adjustments	(11)	(209)	(124)	(61)
Natural Gas Swap [Member] | Issuer [Member]
Other comprehensive income, net of tax:
Derivative adjustments	(11)	(209)	(124)	(61)
Natural Gas Swap [Member] | Guarantors [Member]
Other comprehensive income, net of tax:
Derivative adjustments	0	0	0	0
Natural Gas Swap [Member] | Non-guarantors [Member]
Other comprehensive income, net of tax:
Derivative adjustments	0	0	0	0
Natural Gas Swap [Member] | Eliminations [Member]
Other comprehensive income, net of tax:
Derivative adjustments	0	0	0	0
Corn Option [Member]
Other comprehensive income, net of tax:
Derivative adjustments	621	358	(977)	1,307
Corn Option [Member] | Issuer [Member]
Other comprehensive income, net of tax:
Derivative adjustments	621	358	(977)	1,307
Corn Option [Member] | Guarantors [Member]
Other comprehensive income, net of tax:
Derivative adjustments	0	0	0	0
Corn Option [Member] | Non-guarantors [Member]
Other comprehensive income, net of tax:
Derivative adjustments	0	0	0	0
Corn Option [Member] | Eliminations [Member]
Other comprehensive income, net of tax:
Derivative adjustments	$ 0	$ 0	$ 0	$ 0