Operating Segments (Details) $ in Millions | 3 Months Ended | 9 Months Ended | |
Sep. 30, 2019USD ($) | Sep. 30, 2018USD ($) | Sep. 30, 2019USD ($)Businesssegment | Sep. 30, 2018USD ($) | Dec. 31, 2018USD ($) |
Segment Reporting [Abstract] | | | | | |
Number of reportable segments | segment | | | 3 | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | $ 341.3 | $ 322.5 | $ 990.2 | $ 1,007.1 | |
Operating earnings (loss) | 30.1 | 32.6 | 67.4 | 62 | |
Depreciation, depletion and amortization | 33.9 | 34 | 102.8 | 103.6 | |
Total assets (as of end of period) | 2,329.8 | 2,353 | 2,329.8 | 2,353 | $ 2,367.9 |
United States | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 159.5 | 126 | 526.1 | 498.5 | |
Canada | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 34.2 | 33.4 | 149.5 | 157 | |
Brazil | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 131.7 | 136.3 | 266.4 | 270.3 | |
United Kingdom | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 11 | 17.3 | 34 | 64 | |
Other | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 4.9 | 9.5 | 14.2 | 17.3 | |
Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 54.4 | 51.9 | 215.3 | 221.8 | |
Highway Deicing Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 84.2 | 64 | 349.8 | 360 | |
Consumer & Industrial Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 75.4 | 73 | 228.8 | 214 | |
SOP and Specialty Plant Nutrients | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 157.9 | 162.2 | 344.8 | 358.4 | |
Industrial Chemicals | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 22.9 | 22.9 | 66.8 | 72.7 | |
Operating Segments | Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 159.6 | 137 | 578.6 | 574 | |
Operating earnings (loss) | 20.6 | 12.1 | 87.5 | 58.7 | |
Depreciation, depletion and amortization | 14.3 | 13.7 | 44.4 | 42.5 | |
Total assets (as of end of period) | 959.2 | 918.5 | 959.2 | 918.5 | |
Operating Segments | Salt | Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 43.4 | 41.2 | 184.7 | 190.1 | |
Operating Segments | Salt | Highway Deicing Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 84.2 | 64 | 349.8 | 360 | |
Operating Segments | Salt | Consumer & Industrial Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 75.4 | 73 | 228.8 | 214 | |
Operating Segments | Salt | SOP and Specialty Plant Nutrients | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Operating Segments | Salt | Industrial Chemicals | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Operating Segments | Salt | Eliminations & Other | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Operating Segments | Plant Nutrition North America | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 44.4 | 41.7 | 129.7 | 146.4 | |
Operating earnings (loss) | 4.7 | 2.3 | 7.7 | 11.4 | |
Depreciation, depletion and amortization | 11 | 12.8 | 33.5 | 37.1 | |
Total assets (as of end of period) | 572.8 | 594.5 | 572.8 | 594.5 | |
Operating Segments | Plant Nutrition North America | Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 5.8 | 5 | 18.3 | 17.6 | |
Operating Segments | Plant Nutrition North America | Highway Deicing Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Operating Segments | Plant Nutrition North America | Consumer & Industrial Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Operating Segments | Plant Nutrition North America | SOP and Specialty Plant Nutrients | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 45.7 | 42.8 | 134.1 | 149.9 | |
Operating Segments | Plant Nutrition North America | Industrial Chemicals | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Operating Segments | Plant Nutrition North America | Eliminations & Other | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | (1.3) | (1.1) | $ (4.4) | (3.5) | |
Operating Segments | Plant Nutrition South America | | | | | |
Segment Reporting Information [Line Items] | | | | | |
Number of primary businesses | Business | | | 2 | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 135 | 141.2 | $ 274.8 | 278.6 | |
Operating earnings (loss) | 22.4 | 31.2 | 21.5 | 32.7 | |
Depreciation, depletion and amortization | 6 | 5 | 17 | 16.5 | |
Total assets (as of end of period) | 683.1 | 705.4 | 683.1 | 705.4 | |
Operating Segments | Plant Nutrition South America | Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 5.2 | 5.7 | 12.3 | 14.1 | |
Operating Segments | Plant Nutrition South America | Highway Deicing Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Operating Segments | Plant Nutrition South America | Consumer & Industrial Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Operating Segments | Plant Nutrition South America | SOP and Specialty Plant Nutrients | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 112.2 | 119.4 | 210.7 | 208.5 | |
Operating Segments | Plant Nutrition South America | Industrial Chemicals | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 22.9 | 22.9 | 66.8 | 72.7 | |
Operating Segments | Plant Nutrition South America | Eliminations & Other | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | (0.1) | (1.1) | (2.7) | (2.6) | |
Corporate & Other | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 2.3 | 2.6 | 7.1 | 8.1 | |
Operating earnings (loss) | (17.6) | (13) | (49.3) | (40.8) | |
Depreciation, depletion and amortization | 2.6 | 2.5 | 7.9 | 7.5 | |
Total assets (as of end of period) | 114.7 | 134.6 | 114.7 | 134.6 | |
Corporate & Other | Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 0 | 0 | 0 | 0 | |
Corporate & Other | Highway Deicing Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Corporate & Other | Consumer & Industrial Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Corporate & Other | SOP and Specialty Plant Nutrients | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Corporate & Other | Industrial Chemicals | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Corporate & Other | Eliminations & Other | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 2.3 | 2.6 | 7.1 | 8.1 | |
Intersegment Eliminations | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | (1.4) | (2.2) | (7.1) | (6.1) | |
Intersegment Eliminations | Eliminations & Other | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0.9 | 0.4 | 0 | 2 | |
Intersegment Eliminations | Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Intersegment Eliminations | Plant Nutrition North America | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 1.3 | 1.1 | 4.4 | 3.5 | |
Intersegment Eliminations | Plant Nutrition South America | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | $ 0.1 | $ 1.1 | $ 2.7 | $ 2.6 | |