Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total	$ 156,394	$ 706,927
Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	36,856	206,215
Primary nutrients
Disaggregation of Revenue [Line Items]
Total	60,460	313,967
Service
Disaggregation of Revenue [Line Items]
Total	$ 15,567	$ 48,717
Service | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, percentage of service revenues	10.00%	7.00%
Co-products
Disaggregation of Revenue [Line Items]
Total	$ 29,282	$ 88,390
Other
Disaggregation of Revenue [Line Items]
Total	14,229	49,638
Grain
Disaggregation of Revenue [Line Items]
Total	3,297	11,598
Grain | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	0	0
Grain | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	0	0
Grain | Service
Disaggregation of Revenue [Line Items]
Total	3,052	10,851
Grain | Co-products
Disaggregation of Revenue [Line Items]
Total	0	0
Grain | Other
Disaggregation of Revenue [Line Items]
Total	245	747
Ethanol
Disaggregation of Revenue [Line Items]
Total	31,995	96,408
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	2,713	8,018
Ethanol | Co-products
Disaggregation of Revenue [Line Items]
Total	29,282	88,390
Ethanol | Other
Disaggregation of Revenue [Line Items]
Total	0	0
Plant Nutrient
Disaggregation of Revenue [Line Items]
Total	104,189	542,911
Plant Nutrient | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	36,856	206,215
Plant Nutrient | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	60,460	313,967
Plant Nutrient | Service
Disaggregation of Revenue [Line Items]
Total	877	3,498
Plant Nutrient | Co-products
Disaggregation of Revenue [Line Items]
Total	0	0
Plant Nutrient | Other
Disaggregation of Revenue [Line Items]
Total	5,996	19,231
Rail
Disaggregation of Revenue [Line Items]
Total	16,913	56,010
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	8,925	26,350
Rail | Co-products
Disaggregation of Revenue [Line Items]
Total	0	0
Rail | Other
Disaggregation of Revenue [Line Items]
Total	$ 7,988	$ 29,660