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Stock-Based Compensation (Narrative) (Details) - USD ($) | 1 Months Ended | 12 Months Ended
--- | --- | ---
Oct. 16, 2013 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Stock Based Compensation [Abstract] |  |  |  |
Stock options granted |  | 0 | 0 | 0
Stock options outstanding |  | 0 | 0 | 0
Increase in number of common stock shares authorized | 233,334 |  |  |
Percentage to retain annual restricted stock awards | 50.00% |  |  |
Stock options exercise price description | may not be exercised at a price which is less than 100% of the fair market value of shares at the date of grant |  |  |
Weighted average grant date fair value of restricted stock that vested during |  |  | $ 2,276,000 | $ 2,385,000
Net value of unrecognized compensation cost related to unvested restricted stock awards |  | $ 1,896,000 | 4,195,000 | 4,166,000
Restricted Stock [Member] |  |  |  |
Stock Based Compensation [Abstract] |  |  |  |
Stock-Based Compensation expense |  | $ 2,221,000 | $ 2,129,000 | $ 2,201,000
Shares, Granted |  | 0 | 72,985 | 63,811
Recognized tax benefits |  | $ 235,000 | $ 227,000 | $ 251,000
Stock Option [Member] |  |  |  |
Stock Based Compensation [Abstract] |  |  |  |
Stock-Based Compensation expense |  | $ 0 | $ 0 | $ 0
Class A Common Stock | Stock Option [Member] |  |  |  |
Stock Based Compensation [Abstract] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 990,000 |  |  |
Class A Common Stock | Convert For Class B [Member] |  |  |  |
Stock Based Compensation [Abstract] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 370,000 |  |  |
Class A Common Stock | Incentive Compensation Plan [Member] |  |  |  |
Stock Based Compensation [Abstract] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 620,000 |  |  |
Class B Common Stock |  |  |  |
Stock Based Compensation [Abstract] |  |  |  |
Increase in number of common stock shares authorized | 90,000 |  |  |
Class B Common Stock | Stock Option [Member] |  |  |  |
Stock Based Compensation [Abstract] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 370,000 |  |  |

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- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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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 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)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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