v3.19.1
RECENTLY ADOPTED ACCOUNTING STANDARDS IMPACTS OF ADOPTING ASC 606 ON THE CONSOLIDATED STATEMENT OF OPERATIONS (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
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Lower of cost or net realizable value inventory adjustments $ 930 $ 0 $ 76 $ 705 $ 1,571 $ 666 $ 317 $ 3,825 $ 1,711 $ 6,379 $ 20,374
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)
Net Income (Loss) 7,634 3,350 (958) 1,757 (1,636) (1,445) (5,819) (13,667) 11,783 (22,567) (64,183)
Previously Reported [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Lower of cost or net realizable value inventory adjustments                   7,324  
Gross Margin (Deficit)                   11,545 (29,247)
Net Income (Loss)                   (22,910) (66,633)
Accounting Standards Update 2014-09 [Member] | Restatement Adjustment [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Lower of cost or net realizable value inventory adjustments                   (945)  
Gross Margin (Deficit)                   343 2,450
Net Income (Loss)                   343 2,450
Mineral [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Sales 54,364 41,410 55,176 57,320 42,582 36,484 47,347 51,502 208,270 [1] 177,915 [1] 212,097 [1]
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] | Previously Reported [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Sales                   163,919 210,948
Cost of goods and services sold                   106,341 170,852
Mineral [Member] | Accounting Standards Update 2014-09 [Member] | Restatement Adjustment [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Sales                   13,996 1,149
Cost of goods and services sold                   11,621 (1,107)
Freight costs [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Cost of goods and services sold                 $ 37,052 32,016 36,062
Freight costs [Member] | Previously Reported [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Cost of goods and services sold                   29,039 36,256
Freight costs [Member] | Accounting Standards Update 2014-09 [Member] | Restatement Adjustment [Member]                      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]                      
Cost of goods and services sold                   $ 2,977 $ (194)
[1] 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®.