Revenue (Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total	$ 494,266	$ 356,883	$ 809,438	$ 550,533
Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	119,535	94,281	191,873	169,359
Primary nutrients
Disaggregation of Revenue [Line Items]
Total	197,271	200,288	250,787	253,507
Service
Disaggregation of Revenue [Line Items]
Total	22,266	17,861	36,636	33,150
Products and co-products
Disaggregation of Revenue [Line Items]
Total	87,990	32,462	172,218	59,108
Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	56,767		137,230
Other
Disaggregation of Revenue [Line Items]
Total	10,437	11,991	20,694	35,409
Trade
Disaggregation of Revenue [Line Items]
Total	177,226	3,673	326,797	8,301
Trade | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	31,870	0	35,808	0
Trade | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	22,364	0	22,791	0
Trade | Service
Disaggregation of Revenue [Line Items]
Total	7,745	3,381	8,570	7,799
Trade | Products and co-products
Disaggregation of Revenue [Line Items]
Total	55,943	0	118,701	0
Trade | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	56,767		137,230
Trade | Other
Disaggregation of Revenue [Line Items]
Total	2,537	292	3,697	502
Ethanol
Disaggregation of Revenue [Line Items]
Total	35,629	35,222	60,535	64,413
Ethanol | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	0	0	0	0
Ethanol | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	0	0	0	0
Ethanol | Service
Disaggregation of Revenue [Line Items]
Total	3,547	2,760	6,983	5,305
Ethanol | Products and co-products
Disaggregation of Revenue [Line Items]
Total	32,047	32,462	53,517	59,108
Ethanol | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	0		0
Ethanol | Other
Disaggregation of Revenue [Line Items]
Total	35	0	35	0
Plant Nutrient
Disaggregation of Revenue [Line Items]
Total	270,577	303,105	399,102	438,722
Plant Nutrient | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	87,665	94,281	156,065	169,359
Plant Nutrient | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	174,907	200,288	227,996	253,507
Plant Nutrient | Service
Disaggregation of Revenue [Line Items]
Total	1,696	2,412	1,858	2,621
Plant Nutrient | Products and co-products
Disaggregation of Revenue [Line Items]
Total	0	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	6,309	6,124	13,183	13,235
Rail
Disaggregation of Revenue [Line Items]
Total	10,834	14,883	23,004	39,097
Rail | Specialty nutrients
Disaggregation of Revenue [Line Items]
Total	0	0	0	0
Rail | Primary nutrients
Disaggregation of Revenue [Line Items]
Total	0	0	0	0
Rail | Service
Disaggregation of Revenue [Line Items]
Total	9,278	9,308	19,225	17,425
Rail | Products and co-products
Disaggregation of Revenue [Line Items]
Total	0	0	0	0
Rail | Frac sand and propane
Disaggregation of Revenue [Line Items]
Total	0		0
Rail | Other
Disaggregation of Revenue [Line Items]
Total	$ 1,556	$ 5,575	$ 3,779	$ 21,672