Income Taxes - Summary of Activities Related to Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	$ 1.6	$ 1.9	$ 1.8
Increases related to current year tax	0.0	0.2	0.2
Increases from prior period positions	0.2	0.0	0.0
Decreases from settlements with tax authorities	(0.2)	0.0	0.0
Decreases due to lapse of statute of limitations	(0.3)	(0.5)	(0.1)
Balance at December 31	$ 1.3	$ 1.6	$ 1.9

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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