Stock-Based Compensation and Other Employee Benefit Plans - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Stock-based compensation plans, number of shares available for future grant	3,673,000		3,673,000
Non-cash stock-based compensation expense	$ 6.1	$ 5.6	$ 17.7	$ 15.5
Stock-based compensation, income tax benefits	$ 1.2	$ 1.4	$ 3.4	$ 3.6
Restricted Shares \| Restated 2013 Incentive Plan
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Share-based compensation, number of shares authorized	1,150,000		1,150,000

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

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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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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Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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