Stock-Based Compensation and Other Employee Benefit Plans (Restricted Shares) (Narrative) (Details) - Restricted Shares - USD ($) $ in Millions		3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Stock-based compensation awards, unearned compensation	$ 40.5	$ 40.5		$ 40.5
Stock-based compensation awards, unearned compensation, weighted average expected recognition period (in years)	2 years
Stock-based compensation, vested awards, intrinsic value		$ 0.5	$ 0.9	$ 11.3	$ 6.5

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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
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- Definition

Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

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.

+ References

No definition available.

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