Debt - Long-term Debt (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Long-term debt, gross	$ 208.6	$ 209.2
Less: unamortized debt issuance costs for Term Loan and Series Notes	0.3	0.3
Total debt	208.3	208.9
Less: current portion of long-term debt	2.2	2.2
Long-term debt, net	$ 206.1	206.7
Term Loan, due December 31, 2024 (5.87%)
Debt Instrument [Line Items]
Debt instrument, stated interest rate	5.87%
Long-term debt, gross	$ 82.6	83.2
Long-term debt, net	$ 80.4
Series B notes, due July 5, 2024 (3.82%)
Debt Instrument [Line Items]
Debt instrument, stated interest rate	3.82%
Long-term debt, gross	$ 53.0	53.0
Series C notes, due July 5, 2027 (4.02%)
Debt Instrument [Line Items]
Debt instrument, stated interest rate	4.02%
Long-term debt, gross	$ 73.0	$ 73.0

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

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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.

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Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt classified as noncurrent. Excludes lease obligation.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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No definition available.

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