Investment in Unconsolidated Subsidiary (Assets, Liabilities and members' equity) (Details) - USD ($) $ in Thousands	Mar. 28, 2020	Dec. 31, 2019
ASSETS
Property, plant and equipment, net	$ 779,961	$ 713,489
Diamond Green Diesel Holdings LLC Joint Venture [Member]
ASSETS
Total current assets	821,602	668,026
Other assets	30,446	30,710
Total assets	1,632,009	1,412,225
Liabilities and members' equity:
Total current portion of long term debt	496	341
Total other current liabilities	70,758	75,802
Total long term debt	8,936	8,742
Total other long term liabilities	4,273	4,422
Total liabilities and members' equity	1,547,546	1,322,918
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	$ 1,632,009	$ 1,412,225