Equity-Based Compensation - Time-Based Restricted Stock (Details) - Time-based awards $ / shares in Units, $ in Millions	9 Months Ended
Sep. 30, 2021 USD ($) $ / shares shares
Restricted Stock Units
Nonvested at beginning of period \| shares	1,018,008
Granted \| shares	268,858
Shares vested (including tax withholding) \| shares	(498,446)
Forfeited \| shares	(20,545)
Nonvested at end of period \| shares	767,875
Nonvested at beginning of period, Weighted average grant date fair value per share \| $ / shares	$ 36.74
Granted, Weighted average grant date fair value per share \| $ / shares	39.16
Shares vested (including tax withholding) , Weighted average grant date fair value per share \| $ / shares	37.78
Forfeited, Weighted average grant date fair value per share \| $ / shares	38.05
Nonvested at end of period, Weighted average grant date fair value per share \| $ / shares	$ 36.88
Unrecognized compensation cost \| $	$ 17.6
Period for recognition of RSU compensation expense	1 year 7 months 6 days

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Number of shares under non-option equity instrument agreements that were cancelled as a result of occurrence of a terminating event.

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Net number of non-option equity instruments granted to participants.

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

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