Goodwill and Other Intangible Assets (Changes in Goodwill) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Goodwill at beginning of period	$ 6,024,000	$ 6,024,000	$ 63,934,000
Acquisitions	129,336,000	0	1,171,000
Impairments	0	0	(59,081,000)
Goodwill at end of period	135,360,000	6,024,000	6,024,000
Trade
Goodwill [Roll Forward]
Goodwill at beginning of period	1,171,000	1,171,000	0
Acquisitions	126,610,000	0	1,171,000
Impairments	0	0	0
Goodwill at end of period	127,781,000	1,171,000	1,171,000
Plant Nutrient
Goodwill [Roll Forward]
Goodwill at beginning of period	686,000	686,000	59,767,000
Acquisitions	0	0	0
Impairments	0	0	(59,081,000)
Goodwill at end of period	686,000	686,000	686,000
Rail
Goodwill [Roll Forward]
Goodwill at beginning of period	4,167,000	4,167,000	4,167,000
Acquisitions	0	0	0
Impairments	0	0	0
Goodwill at end of period	4,167,000	4,167,000	4,167,000
Ethanol
Goodwill [Roll Forward]
Goodwill at beginning of period	0	0	0
Acquisitions	2,726,000	0	0
Impairments	0	0	0
Goodwill at end of period	$ 2,726,000	$ 0	$ 0