Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total	$ 356,883	$ 550,533
Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	94,281	169,359
Primary nutrients
Disaggregation of Revenue [Line Items]
Total	200,288	253,507
Service
Disaggregation of Revenue [Line Items]
Total	$ 17,861	$ 33,150
Service | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenue from contract with customer, percentage of service revenues	5.00%	6.00%
Co-products
Disaggregation of Revenue [Line Items]
Total	$ 32,462	$ 59,108
Other
Disaggregation of Revenue [Line Items]
Total	11,991	35,409
Grain
Disaggregation of Revenue [Line Items]
Total	3,673	8,301
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	3,381	7,799
Grain | Co-products
Disaggregation of Revenue [Line Items]
Total	0	0
Grain | Other
Disaggregation of Revenue [Line Items]
Total	292	502
Ethanol
Disaggregation of Revenue [Line Items]
Total	35,222	64,413
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	2,760	5,305
Ethanol | Co-products
Disaggregation of Revenue [Line Items]
Total	32,462	59,108
Ethanol | Other
Disaggregation of Revenue [Line Items]
Total	0	0
Plant Nutrient
Disaggregation of Revenue [Line Items]
Total	303,105	438,722
Plant Nutrient | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	94,281	169,359
Plant Nutrient | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	200,288	253,507
Plant Nutrient | Service
Disaggregation of Revenue [Line Items]
Total	2,412	2,621
Plant Nutrient | Co-products
Disaggregation of Revenue [Line Items]
Total	0	0
Plant Nutrient | Other
Disaggregation of Revenue [Line Items]
Total	6,124	13,235
Rail
Disaggregation of Revenue [Line Items]
Total	14,883	39,097
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	9,308	17,425
Rail | Co-products
Disaggregation of Revenue [Line Items]
Total	0	0
Rail | Other
Disaggregation of Revenue [Line Items]
Total	$ 5,575	$ 21,672