Basis of Presentation and Significant Accounting Policies - Property and Equipment Included in Other Assets (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Property and Equipment
Property and equipment	$ 136.4	$ 131.3
Less: accumulated depreciation	70.4	66.6
Total	$ 66.0	$ 64.7

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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