The maximum amount of the facility's borrowing capacity that may be drawn in British pounds sterling.

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The maximum amount of the facility's borrowing capacity that may be drawn in Canadian dollars.

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Debt Instrument, Variable Rate, Percentage Of Reference Rate

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Amount of amortization expense attributable to debt issuance costs.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Gross amount of debt extinguished.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Weighted average interest rate of long-term debt outstanding calculated at point in time.

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The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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Amount of a short-term obligation that has been excluded from current liabilities in the balance sheet because of a refinancing of the obligation.

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Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

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LONG TERM DEBT (Additional Information) (Details)		1 Months Ended		3 Months Ended			12 Months Ended
LONG TERM DEBT (Additional Information) (Details)	Oct. 31, 2019	Nov. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) loan	Mar. 31, 2019 USD ($) loan	Sep. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2019 USD ($)
Debt Instrument [Line Items]
Debt outstanding			$ 1,371,400,000	$ 1,430,800,000			$ 1,430,800,000	$ 1,371,400,000
Expense as result of amendment							2,800,000	2,200,000	$ 2,200,000
Short-term debt refinanced				17,400,000
2019 Credit Agreement
Debt Instrument [Line Items]
Weighted average interest rate on all borrowings outstanding		3.80%
Fees paid as a result of amendment		$ 4,100,000
Capitalized deferred financing costs as result of amendment		3,800,000
Expense as result of amendment		300,000
Write off of previously capitalized deferred financing costs		300,000
Term Loan due January 2025
Debt Instrument [Line Items]
Debt outstanding			0	400,000,000.0			400,000,000.0	0
Revolving Credit Facility due January 2025
Debt Instrument [Line Items]
Debt outstanding			0	160,000,000.0			160,000,000.0	0
Revolving Credit Facility due July 2021
Debt Instrument [Line Items]
Debt outstanding			197,000,000.0	0			0	197,000,000.0
4.875% Senior Notes due July 2024
Debt Instrument [Line Items]
Debt outstanding			250,000,000.0	$ 250,000,000.0			$ 250,000,000.0	250,000,000.0
Stated interest rate				4.875%			4.875%
6.75% Senior Notes due December 2027
Debt Instrument [Line Items]
Debt outstanding			0	$ 500,000,000.0			$ 500,000,000.0	0
Stated interest rate				6.75%			6.75%
Compass Minerals South America Loan Mature from March 2020 through November 2023
Debt Instrument [Line Items]
Face amount				$ 120,800,000			$ 120,800,000
Brazilian loans
Debt Instrument [Line Items]
Face amount			$ 18,400,000			$ 20,000,000.0		$ 18,400,000
Debt extinguishment amount						$ 36,000,000
Brazilian loans \| Certificado De Deposito Interbancario (CDI)
Debt Instrument [Line Items]
Variable rate, percentage of reference rate			133.10%			117.50%		133.10%
Brazilian Reais-denominated Loans
Debt Instrument [Line Items]
Face amount				$ 27,300,000	$ 18,000,000.0		$ 27,300,000			$ 36,000,000.0
Number of loans \| loan				2	2
Brazilian Reais-denominated Loan Matured In July 2019 \| Certificado De Deposito Interbancario (CDI)
Debt Instrument [Line Items]
Variable rate, percentage of reference rate					123.00%
Brazilian Reais-denominated Loan Matured In September 2019 \| Certificado De Deposito Interbancario (CDI)
Debt Instrument [Line Items]
Variable rate, percentage of reference rate					128.00%
Brazilian Reais-denominated Loans Mature In July 2021 \| Certificado De Deposito Interbancario (CDI)
Debt Instrument [Line Items]
Variable rate, percentage of reference rate										120.00%
Brazilian Reais-denominated Loans Mature September 2021, one \| Certificado De Deposito Interbancario (CDI)
Debt Instrument [Line Items]
Variable rate, percentage of reference rate										141.00%
Brazilian Reais-denominated Loans Mature September 2021, two \| Certificado De Deposito Interbancario (CDI)
Debt Instrument [Line Items]
Variable rate, percentage of reference rate				126.00%			126.00%
Brazilian Reais-denominated Loans Mature December 2021 \| Certificado De Deposito Interbancario (CDI)
Debt Instrument [Line Items]
Variable rate, percentage of reference rate				129.00%			129.00%
Brazilian Reais-Denominated Loans Mature November 2021 \| Certificado De Deposito Interbancario (CDI)
Debt Instrument [Line Items]
Variable rate, percentage of reference rate				122.00%			122.00%
Banco Rabobank loan due November 2021
Debt Instrument [Line Items]
Debt outstanding			$ 0	$ 17,400,000			$ 17,400,000	$ 0
Revolving credit facility \| Revolving Credit Facility due July 2021
Debt Instrument [Line Items]
Fees paid as a result of amendment			1,400,000
Capitalized deferred financing costs as result of amendment			1,400,000					$ 1,400,000
Expense as result of amendment			$ 100,000
Secured debt \| Base Rate
Debt Instrument [Line Items]
Interest spread over base rate	0.50%
Secured debt \| Term Loan due January 2025
Debt Instrument [Line Items]
Face amount		$ 400,000,000
Principal payments as a percentage, years one and two		2.50%
Principal payments as a percentage, years three through five		5.00%
Line of credit \| Revolving credit facility \| Revolving Credit Facility due January 2025
Debt Instrument [Line Items]
Long-term debt, revolving credit facility		$ 300,000,000
Amount of facility that may be drawn in Canadian dollars				40,000,000			40,000,000
Amount of facility that may be drawn in British pounds sterling				10,000,000			10,000,000
Remaining borrowing capacity				129,500,000			129,500,000
Line of credit \| Letter of credit \| Revolving Credit Facility due January 2025
Debt Instrument [Line Items]
Long-term debt, revolving credit facility				50,000,000			50,000,000
Outstanding letters of credit				$ 10,500,000			$ 10,500,000
Senior notes \| 4.875% Senior Notes due July 2024
Debt Instrument [Line Items]
Stated interest rate				4.875%			4.875%
Senior notes \| 6.75% Senior Notes due December 2027
Debt Instrument [Line Items]
Face amount		500,000,000
Capitalized deferred financing costs as result of amendment		$ 8,200,000
Stated interest rate		6.75%		6.75%			6.75%