Stock-Based Compensation (Narrative) (Details) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense	$ 0
Forfeitures related to departure		$ 1,700,000
Share performance-based, cumulative profit target (in shares)		50,000
Cumulative profit target	5 years
Total fair value of restricted stock units vested	$ 6,400,000	$ 8,000,000.0	$ 8,300,000
Unrecognized compensation expense	$ 10,100,000
Total weighted average period	2 years 1 month 6 days
Restricted shares and performance shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Compensation expense	$ 6,100,000	$ 4,100,000	$ 8,300,000

Share-Based Compensation Arrangement By Share-Based Payment Award, Cumulative Profit Target

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- Definition

Share-Based Compensation Arrangement By Share-Based Payment Award, Cumulative Profit Target Period

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- Definition

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

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

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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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The total value of forfeitures related to restricted stock awards forfeited during the period.

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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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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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