Incentive Plans (Summary of Awards Granted) (Details)	6 Months Ended
Jun. 30, 2021 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Threshold of executive compensation not eligible for U.S. income tax deduction \| $	$ 1,000,000.0
2020 Long-Term Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares available for issuance (in shares)	5,000,000
Performance-Based RSUs \| 2020 Long-Term Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	1,156,800
Fair value per share at grant date (in USD per share) \| $ / shares	$ 16.03
Time-Based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value per share at grant date (in USD per share) \| $ / shares	$ 12.30
Time-Based RSUs \| 2020 Long-Term Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	385,600
Time-Based RSUs \| 2018 NED Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	182,652
Fair value per share at grant date (in USD per share) \| $ / shares	$ 13.14
Time-Based RSUs \| 2021 NED Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	5,655
Fair value per share at grant date (in USD per share) \| $ / shares	$ 23.58
Cash Settled RSUs \| 2020 Long-Term Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	1,022,700
Fair value per share at grant date (in USD per share) \| $ / shares	$ 12.30

Tax Cuts and Jobs Act of 2017, Threshold of Deductible Compensation For Executive Officers

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- Definition

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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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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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-SubTopic 10
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-Paragraph 2
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