Long-Term Incentive Compensation - Stock Option Activity (Details) shares in Thousands	3 Months Ended
Mar. 31, 2021 $ / shares shares
Stock Options
Outstanding, beginning balance (in shares)	530
Granted (in shares)	0
Vested (in shares)	0
Forfeited (in shares)	(80)
Outstanding, ending balance (in shares)	450
Weighted average grant date fair value (2021 awards) (in dollars per share) \| $ / shares	$ 0
Service-based Restricted Stock
Service-based and Performance-based Stock
Outstanding, beginning balance (in shares)	1,087
Granted (in shares)	446
Vested (in shares)	(506)
Forfeited (in shares)	(15)
Outstanding, ending balance (in shares)	1,012
Weighted average grant date fair value (2021 awards) (in dollars per share) \| $ / shares	$ 6.87
Performance-based Stock Units
Service-based and Performance-based Stock
Outstanding, beginning balance (in shares)	287
Granted (in shares)	245
Vested (in shares)	(70)
Forfeited (in shares)	(42)
Outstanding, ending balance (in shares)	420
Weighted average grant date fair value (2021 awards) (in dollars per share) \| $ / shares	$ 6.84

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

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 (c)(1)(iv)(3)
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The number of grants made 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).

+ References

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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.

+ References

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-Name Accounting Standards Codification
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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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-Publisher FASB
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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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-Publisher FASB
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- Definition

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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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Number of options vested.

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Weighted average grant-date fair value of options vested.

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