Stock-Based Compensation - Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense, before income taxes	$ 22.3	$ 20.2	$ 20.5
Tax benefit	(1.5)	(1.3)	(2.0)
Stock-based compensation expense, net of tax	20.8	18.9	18.5
Restricted Stock Units and Performance Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense, before income taxes	22.3	20.2	20.3
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense, before income taxes	$ 0.0	$ 0.0	$ 0.2

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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