Operating Segments (Details) $ in Millions | 3 Months Ended | 9 Months Ended | |
Sep. 30, 2018USD ($) | Sep. 30, 2017USD ($) | Sep. 30, 2018USD ($)Businesssegment | Sep. 30, 2017USD ($) | Dec. 31, 2017USD ($) |
Segment Reporting Information [Line Items] | | | | | |
Number of reportable segments (in segments) | segment | | | 3 | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | $ 322.5 | $ 290.7 | $ 1,007.1 | $ 906.5 | |
Operating earnings (loss) | 32.6 | 31.4 | 62 | 78.8 | |
Depreciation, depletion and amortization | 34 | 32.7 | 103.6 | 89.1 | |
Total assets (as of end of period) | 2,353 | 2,446.8 | 2,353 | 2,446.8 | $ 2,571 |
United States | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 126 | | 498.5 | | |
Canada | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 33.4 | | 157 | | |
Brazil | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 136.3 | | 270.3 | | |
United Kingdom | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 17.3 | | 64 | | |
Other | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 9.5 | | 17.3 | | |
Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 51.9 | 45.5 | 221.8 | 179.8 | |
Operating segments | Highway Deicing Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 64 | | 360 | | |
Operating segments | Consumer & Industrial Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 73 | | 214 | | |
Operating segments | SOP and Specialty Plant Nutrients | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 162.2 | | 358.4 | | |
Operating segments | Industrial Chemicals | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 22.9 | | 72.7 | | |
Operating segments | Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 137 | 124.7 | 574 | 508.5 | |
Operating earnings (loss) | 12.1 | 22.5 | 58.7 | 78.6 | |
Depreciation, depletion and amortization | 13.7 | 13.5 | 42.5 | 39.1 | |
Total assets (as of end of period) | 918.5 | 948.7 | 918.5 | 948.7 | |
Operating segments | Salt | Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 41.2 | 34.9 | 190.1 | 147.6 | |
Operating segments | Salt | Highway Deicing Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 64 | | 360 | | |
Operating segments | Salt | Consumer & Industrial Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 73 | | 214 | | |
Operating segments | Salt | SOP and Specialty Plant Nutrients | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | | 0 | | |
Operating segments | Salt | Industrial Chemicals | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | | 0 | | |
Operating segments | Plant Nutrition North America | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 41.7 | 40.3 | 146.4 | 140 | |
Operating earnings (loss) | 2.3 | 2.3 | 11.4 | 17.5 | |
Depreciation, depletion and amortization | 12.8 | 9.2 | 37.1 | 26.7 | |
Total assets (as of end of period) | 594.5 | 593.1 | 594.5 | 593.1 | |
Operating segments | Plant Nutrition North America | Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 5 | 4.8 | 17.6 | 18.4 | |
Operating segments | Plant Nutrition North America | Highway Deicing Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | | 0 | | |
Operating segments | Plant Nutrition North America | Consumer & Industrial Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | | 0 | | |
Operating segments | Plant Nutrition North America | SOP and Specialty Plant Nutrients | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 42.8 | | 149.9 | | |
Operating segments | Plant Nutrition North America | Industrial Chemicals | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | | $ 0 | | |
Operating segments | Plant Nutrition South America | | | | | |
Segment Reporting Information [Line Items] | | | | | |
Number of primary businesses (in businesses) | Business | | | 2 | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 141.2 | 123.2 | $ 278.6 | 250.6 | |
Operating earnings (loss) | 31.2 | 21.4 | 32.7 | 24 | |
Depreciation, depletion and amortization | 5 | 7.5 | 16.5 | 18.2 | |
Total assets (as of end of period) | 705.4 | 844.2 | 705.4 | 844.2 | |
Operating segments | Plant Nutrition South America | Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 5.7 | 5.8 | 14.1 | 13.8 | |
Operating segments | Plant Nutrition South America | Highway Deicing Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | | 0 | | |
Operating segments | Plant Nutrition South America | Consumer & Industrial Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | | 0 | | |
Operating segments | Plant Nutrition South America | SOP and Specialty Plant Nutrients | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 119.4 | | 208.5 | | |
Operating segments | Plant Nutrition South America | Industrial Chemicals | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 22.9 | | 72.7 | | |
Corporate & other | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 2.6 | 2.5 | 8.1 | 7.4 | |
Operating earnings (loss) | (13) | (14.8) | (40.8) | (41.3) | |
Depreciation, depletion and amortization | 2.5 | 2.5 | 7.5 | 5.1 | |
Total assets (as of end of period) | 134.6 | 60.8 | 134.6 | 60.8 | |
Corporate & other | Shipping and handling cost | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Shipping and handling cost | 0 | 0 | 0 | 0 | |
Intersegment sales | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | (2.2) | (1.5) | (6.1) | (4.4) | |
Intersegment sales | Salt | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 0 | 0 | 0 | 0 | |
Intersegment sales | Plant Nutrition North America | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 1.1 | 1.5 | 3.5 | 4.4 | |
Intersegment sales | Plant Nutrition South America | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 1.1 | $ 0 | 2.6 | $ 0 | |
Corporate, reconciling items, and eliminations | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | 2.6 | | 8.1 | | |
Corporate and reconciling items | | | | | |
Segment Reporting Information [Abstract] | | | | | |
Sales | $ 0.4 | | $ 2 | | |