Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total	$ 315,172	$ 193,650
Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	72,338	75,078
Primary nutrients
Disaggregation of Revenue [Line Items]
Total	53,516	53,219
Service
Disaggregation of Revenue [Line Items]
Total	$ 14,370	$ 15,289
Service | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, percentage of service revenues	5.00%	8.00%
Products and co-products
Disaggregation of Revenue [Line Items]
Total	$ 84,230
Co-products
Disaggregation of Revenue [Line Items]
Total		$ 26,646
Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	80,463
Other
Disaggregation of Revenue [Line Items]
Total	10,255	23,418
Trade
Disaggregation of Revenue [Line Items]
Total	149,568	4,628
Trade | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	3,938	0
Trade | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	427	0
Trade | Service
Disaggregation of Revenue [Line Items]
Total	825	4,418
Trade | Products and co-products
Disaggregation of Revenue [Line Items]
Total	62,758
Trade | Co-products
Disaggregation of Revenue [Line Items]
Total		0
Trade | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	80,463
Trade | Other
Disaggregation of Revenue [Line Items]
Total	1,157	210
Ethanol
Disaggregation of Revenue [Line Items]
Total	24,908	29,191
Ethanol | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	0	0
Ethanol | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	0	0
Ethanol | Service
Disaggregation of Revenue [Line Items]
Total	3,436	2,545
Ethanol | Products and co-products
Disaggregation of Revenue [Line Items]
Total	21,472
Ethanol | Co-products
Disaggregation of Revenue [Line Items]
Total		26,646
Ethanol | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	0
Ethanol | Other
Disaggregation of Revenue [Line Items]
Total		0
Plant Nutrient
Disaggregation of Revenue [Line Items]
Total	128,525	135,617
Plant Nutrient | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	68,400	75,078
Plant Nutrient | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	53,089	53,219
Plant Nutrient | Service
Disaggregation of Revenue [Line Items]
Total	162	209
Plant Nutrient | Products and co-products
Disaggregation of Revenue [Line Items]
Total	0
Plant Nutrient | Co-products
Disaggregation of Revenue [Line Items]
Total		0
Plant Nutrient | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	0
Plant Nutrient | Other
Disaggregation of Revenue [Line Items]
Total	6,874	7,111
Rail
Disaggregation of Revenue [Line Items]
Total	12,171	24,214
Rail | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	0	0
Rail | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	0	0
Rail | Service
Disaggregation of Revenue [Line Items]
Total	9,947	8,117
Rail | Products and co-products
Disaggregation of Revenue [Line Items]
Total	0
Rail | Co-products
Disaggregation of Revenue [Line Items]
Total		0
Rail | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	0
Rail | Other
Disaggregation of Revenue [Line Items]
Total	$ 2,224	$ 16,097