Comprehensive Income Reclassifications (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Oct. 01, 2016	Jul. 02, 2016	Apr. 02, 2016	Jan. 02, 2016	Oct. 03, 2015	Jul. 04, 2015	Apr. 04, 2015	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales and operating expenses										$ 2,641,734	$ 2,654,025	$ 3,123,171
Amortization of prior service cost										(36)	67	(23)
Amortization of actuarial loss										4,632	5,101	2,078
Amortization of curtailment										0	(1,181)
Amortization of settlement										(114)	5,291
Income taxes										(15,315)	(13,501)	(13,141)
Net income		$ 40,541	$ 28,694	$ 31,999	$ 1,079	$ 84,429	$ (9,087)	$ 3,080	$ 109	102,313	78,531	64,215
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income										(434)	(5,126)	1,201
Reclassification out of Accumulated Other Comprehensive Income [Member] | Derivative Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income from operations before income taxes										3,868	1,517	4,064
Income taxes										(1,501)	(589)	(1,577)
Net income										2,367	928	2,487
Reclassification out of Accumulated Other Comprehensive Income [Member] | Derivative Instruments | Natural Gas Swap [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales and operating expenses										0	0	196
Reclassification out of Accumulated Other Comprehensive Income [Member] | Derivative Instruments | Corn Option [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales and operating expenses										3,868	1,517	3,868
Reclassification out of Accumulated Other Comprehensive Income [Member] | Defined Benefit Pension Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service cost	[1]									(36)	67	(23)
Amortization of actuarial loss	[1]									(4,632)	(5,101)	(2,078)
Amortization of curtailment	[1]									0	1,181	0
Amortization of settlement	[1]									114	(5,291)	0
Income from operations before income taxes										(4,554)	(9,144)	(2,101)
Income taxes										1,753	3,090	815
Net income										$ (2,801)	$ (6,054)	$ (1,286)

[1] These items are included in the computation of net periodic pension cost. See Note 15 Employee Benefit Plans for additional information.