FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair value of financial instruments
Restricted Cash	$ 2.3	$ 3.9	$ 5.3
Carrying value
Fair value of financial instruments
Cash and cash equivalents	134.0	249.8
Restricted Cash	2.3	3.9
Capital construction fund	599.4	518.2
Fixed rate debt	440.6	517.5
Fair Value Measurement
Fair value of financial instruments
Cash and cash equivalents	134.0	249.8
Restricted Cash	2.3	3.9
Capital construction fund	599.4	518.2
Fixed rate debt	359.9	427.3
Fair Value Measurement \| Quoted Prices in Active Markets (Level 1)
Fair value of financial instruments
Cash and cash equivalents	134.0	249.8
Restricted Cash	2.3	3.9
Capital construction fund	599.4	518.2
Fair Value Measurement \| Significant Observable Inputs (Level 2)
Fair value of financial instruments
Fixed rate debt	$ 359.9	$ 427.3

The balance of cash on deposit in capital construction fund.

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

The portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

+ References

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- Definition

Amount of cash and cash equivalents restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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