Investment in Unconsolidated Subsidiary Selected Financial Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Assets:
Property, plant and equipment, net		$ 354,871		$ 435,328
Total assets		635,769		642,761
Liabilities and members' equity:
Total current portion of long term debt		17,023		17,023
Total long term debt		53,753		36,730
Total members' equity		541,375		547,853
Expenses:
Operating income	$ 57,441	146,627	$ 157,274
Interest and debt expense, net	(2,306)	(7,354)	(13,604)
Diamond Green Diesel Holdings LLC Joint Venture [Member]
Assets:
Total current assets		268,734		202,778
Other assets		12,164		4,655
Liabilities and members' equity:
Total other current liabilities		23,200		40,705
Total other long term liabilities		418		450
Total liabilities and member's equity		635,769		$ 642,761
Revenues:
Operating revenues	633,908	527,670	475,934
Equity Method Investment, Summarized Financial Information, Total Costs and Expenses Less Depreciation, Amortization and Accretion Expense	547,512	353,222	298,946
Equity Method Investment, Summarized Financial Information, Depreciation, Amortization and Accretion Expense	28,955	27,821	19,714
Expenses:
Other income	1,343	551	120
Net income	$ 56,478	$ 139,824	$ 143,790