Stock-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved under plan	4,500,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of stock option or unit granted	10 years
Stock option vesting period option	3 years
Percentage of stock options to become vested and exercisable	100.00%
Weighted-average grant-date fair value	$ 5.28	$ 6.47	$ 8.91
Recognized stock-based compensation expense	$ 2,304	$ 1,801	$ 1,528
Unearned compensation cost related to the unvested portion of all stock-based awards	$ 2,039	$ 1,469	$ 606
Performance Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of stock option or unit granted	3 years
Number of share based compensation units granted	284,894
Maximum payout percentage	200.00%
Weighted-average grant-date fair value	$ 14.64	$ 17.61	$ 22.92
Vesting period	3 years
Recognized stock-based compensation expense	$ 3,270	$ 3,607	$ 4,152
Unearned compensation cost related to the unvested portion of all stock-based awards	$ 3,417	$ 2,730	$ 3,599
Performance Share Units Associated With 2020 Grants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares outstanding	200,000
Performance Share Units Associated With 2019 Grants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares outstanding	200,000
Restricted Stock Units[Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share based compensation units granted	200,000	200,000	100,000
Vesting period	3 years
Recognized stock-based compensation expense	$ 2,400	$ 1,700	$ 2,200
Unearned compensation cost related to the unvested portion of all stock-based awards	$ 2,800	$ 2,800	$ 2,800
Director's Deferred Compensation [Member] \| Common Shares in Treasury [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock held in rabbi trust	100,000	100,000
Value of common stock held in rabbi trust	$ 1,600	$ 1,600

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Share Based Compensation Arrangement By Share Based Payment Award Percentage Vested Upon Death Retirement Or Change In Control

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Share Based Compensation Arrangement By Share Based Payment Award Terms Of Award 1

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

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Value of common stock issued to a trust (for example, a 'rabbi trust') set up specifically to accumulate stock for the sole purpose of distribution to participating employees. This trust does not allow employees to immediately or after a holding period diversify into nonemployer securities. The deferred compensation plan for which this trust is set up must be settled by the delivery of a fixed number of shares of employer stock.

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

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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.

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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).

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

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Number of shares issued which are neither cancelled nor held in the treasury.

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