Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total	$ 1,527,141	$ 1,391,848	$ 898,885
Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	234,806	285,116	260,821
Primary nutrients
Disaggregation of Revenue [Line Items]
Total	396,515	411,260	399,566
Service
Disaggregation of Revenue [Line Items]
Total	50,990	63,011	65,042
Products and co-products
Disaggregation of Revenue [Line Items]
Total	642,896	348,475	114,489
Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	148,175	238,100
Other
Disaggregation of Revenue [Line Items]
Total	53,759	45,886	58,967
Trade
Disaggregation of Revenue [Line Items]
Total	405,993	556,816	12,382
Trade | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	0	46,065	0
Trade | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	0	33,612	0
Trade | Service
Disaggregation of Revenue [Line Items]
Total	9,030	13,108	11,347
Trade | Products and co-products
Disaggregation of Revenue [Line Items]
Total	234,219	217,297	0
Trade | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	148,175	238,100
Trade | Other
Disaggregation of Revenue [Line Items]
Total	14,569	8,634	1,035
Ethanol
Disaggregation of Revenue [Line Items]
Total	410,734	140,813	128,594
Ethanol | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	0	0	0
Ethanol | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	0	0	0
Ethanol | Service
Disaggregation of Revenue [Line Items]
Total	0	8,775	14,105
Ethanol | Products and co-products
Disaggregation of Revenue [Line Items]
Total	408,677	131,178	114,489
Ethanol | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	0	0
Ethanol | Other
Disaggregation of Revenue [Line Items]
Total	2,057	860	0
Plant Nutrient
Disaggregation of Revenue [Line Items]
Total	662,959	646,730	690,536
Plant Nutrient | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	234,806	239,051	260,821
Plant Nutrient | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	396,515	377,648	399,566
Plant Nutrient | Service
Disaggregation of Revenue [Line Items]
Total	5,108	4,202	4,411
Plant Nutrient | Products and co-products
Disaggregation of Revenue [Line Items]
Total	0	0	0
Plant Nutrient | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	0	0
Plant Nutrient | Other
Disaggregation of Revenue [Line Items]
Total	26,530	25,829	25,738
Rail
Disaggregation of Revenue [Line Items]
Total	47,455	47,489	67,373
Rail | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	0	0	0
Rail | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	0	0	0
Rail | Service
Disaggregation of Revenue [Line Items]
Total	36,852	36,926	35,179
Rail | Products and co-products
Disaggregation of Revenue [Line Items]
Total	0	0	0
Rail | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	0	0
Rail | Other
Disaggregation of Revenue [Line Items]
Total	$ 10,603	$ 10,563	$ 32,194