v3.19.1
BUSINESS SEGMENTS (Information by Segment) (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Segment Reporting Information [Line Items]                      
Lower of cost or NRV $ 930 $ 0 $ 76 $ 705 $ 1,571 $ 666 $ 317 $ 3,825 $ 1,711 $ 6,379 $ 20,374
Costs associated with abnormal production and other                     1,707
Gross Margin (Deficit) 14,826 8,959 7,286 7,200 3,628 6,062 4,803 (2,605) 38,271 11,888 (26,797)
Depreciation, depletion and amortization expense [1]                 32,215 33,209 40,913
Operating Segments [Member] | Potash [Member]                      
Segment Reporting Information [Line Items]                      
Lower of cost or NRV                 0 550 18,379
Costs associated with abnormal production and other                     650
Gross Margin (Deficit)                 29,008 15,670 (25,398)
Depreciation, depletion and amortization expense [1]                 25,134 26,485 30,708
Operating Segments [Member] | Trio [Member]                      
Segment Reporting Information [Line Items]                      
Lower of cost or NRV                 1,711 5,829 1,995
Costs associated with abnormal production and other                     1,057
Gross Margin (Deficit)                 (3,782) (9,548) (1,399)
Depreciation, depletion and amortization expense [1]                 6,343 6,576 9,296
Operating Segments [Member] | Oil Field Solutions [Member]                      
Segment Reporting Information [Line Items]                      
Lower of cost or NRV                 0 0 0
Costs associated with abnormal production and other                     0
Gross Margin (Deficit)                 13,045 5,766 0
Depreciation, depletion and amortization expense [1]                 343 19 0
Corporate/Other [Member]                      
Segment Reporting Information [Line Items]                      
Depreciation, depletion and amortization expense [1]                 395 129 909
Freight costs [Member]                      
Segment Reporting Information [Line Items]                      
Cost of goods and services sold                 37,052 32,016 36,062
Freight costs [Member] | Operating Segments [Member] | Potash [Member]                      
Segment Reporting Information [Line Items]                      
Cost of goods and services sold                 17,682 13,912 25,732
Freight costs [Member] | Operating Segments [Member] | Trio [Member]                      
Segment Reporting Information [Line Items]                      
Cost of goods and services sold                 19,370 18,104 10,330
Freight costs [Member] | Operating Segments [Member] | Oil Field Solutions [Member]                      
Segment Reporting Information [Line Items]                      
Cost of goods and services sold                 0 0 0
Warehouse and handling costs [Member]                      
Segment Reporting Information [Line Items]                      
Cost of goods and services sold                 9,281 9,670 11,006
Warehouse and handling costs [Member] | Operating Segments [Member] | Potash [Member]                      
Segment Reporting Information [Line Items]                      
Cost of goods and services sold                 5,046 5,556 8,438
Warehouse and handling costs [Member] | Operating Segments [Member] | Trio [Member]                      
Segment Reporting Information [Line Items]                      
Cost of goods and services sold                 4,225 4,114 2,568
Warehouse and handling costs [Member] | Operating Segments [Member] | Oil Field Solutions [Member]                      
Segment Reporting Information [Line Items]                      
Cost of goods and services sold                 10 0 0
Warehouse and handling costs [Member] | Corporate/Other [Member]                      
Segment Reporting Information [Line Items]                      
Cost of goods and services sold                  
Mineral [Member]                      
Segment Reporting Information [Line Items]                      
Sales 54,364 41,410 55,176 57,320 42,582 36,484 47,347 51,502 208,270 [2] 177,915 [2] 212,097 [2]
Cost of goods and services sold $ 26,504 $ 23,370 $ 35,426 $ 36,655 $ 26,481 $ 21,414 $ 31,735 $ 38,332 121,955 117,962 169,745
Mineral [Member] | Operating Segments [Member] | Potash [Member]                      
Segment Reporting Information [Line Items]                      
Sales [2]                 124,058 107,917 159,207
Cost of goods and services sold                 72,322 72,229 131,406
Mineral [Member] | Operating Segments [Member] | Trio [Member]                      
Segment Reporting Information [Line Items]                      
Sales [2]                 66,808 63,686 52,890
Cost of goods and services sold                 45,284 45,187 38,339
Mineral [Member] | Operating Segments [Member] | Oil Field Solutions [Member]                      
Segment Reporting Information [Line Items]                      
Sales [2]                 17,404 6,312 0
Cost of goods and services sold                 $ 4,349 $ 546 $ 0
[1] Depreciation and depletion incurred for potash and Trio® excludes depreciation and depletion absorbed in or (relieved from) inventory.
[2] Segment sales include the sales of byproducts generated during the production of potash and Trio®. Prior to the adoption of ASC 606, sales of byproducts were accounted for as a credit to cost of goods sold for potash and Trio®.