Long-Term Debt - Summary of Senior Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Term loan, bearing interest at variable rates (rate of 1.90% as of December 31, 2020), maturing in September 2023	$ 608.5
Total senior debt	307.1	$ 326.3
Term loan
Debt Instrument [Line Items]
Term loan, bearing interest at variable rates (rate of 1.90% as of December 31, 2020), maturing in September 2023	308.5	328.1
Unamortized deferred financing costs	(1.4)	(1.8)
Total senior debt	$ 307.1	$ 326.3
Term loan, bearing interest at variable rates	1.90%

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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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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The interest rate applicable to 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 rate subject to change from time to time.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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