Equity-Based Incentive Plans (2018 Executive Incentive Compensation Plan) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Performance/Service period one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	100.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	2 years
Executive Incentive Compensation Plan 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	2,000,000.0
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	33.33%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,500,000	1,700,000	1,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	148,000	149,000	157,000
Award Market Value	$ 5.1	$ 4.5	$ 5.8
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	2 years

Represents the market value of awards granted during the year.

No definition available.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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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.

+ References

No definition available.

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- Definition

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

+ References

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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-Publisher FASB
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- Definition

Percentage of vesting of award under share-based payment arrangement.

+ References

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