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Stock Options Outstanding Table (Details) - $ / shares | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Text Block [Abstract] |  |  |  |
Beginning outstanding, shares | 351,561 | 395,353 | 540,441 | 540,441
Weighted Average Exercise Price | $ 96.97 | $ 96.37 | $ 96.35 | $ 96.35
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Beginning outstanding, shares | 351,561 | 395,353 | 540,441 | 540,441
Weighted Average Exercise Price | $ 96.97 | $ 96.37 | $ 96.35 | $ 96.35
Exercise price of $86.86 |  |  |  |
Text Block [Abstract] |  |  |  |
Beginning outstanding, shares | 54,003 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 1 month 6 days |  |  |
Weighted Average Exercise Price | $ 86.86 |  |  |
Number Exercisable | 54,003 |  |  |
Exercisable, Weighted Average Exercise Price | $ 86.86 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Beginning outstanding, shares | 54,003 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 1 month 6 days |  |  |
Weighted Average Exercise Price | $ 86.86 |  |  |
Number Exercisable | 54,003 |  |  |
Exercisable, Weighted Average Exercise Price | $ 86.86 |  |  |
Exercise price $95.69 |  |  |  |
Text Block [Abstract] |  |  |  |
Beginning outstanding, shares | 54,282 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 2 years 3 months 18 days |  |  |
Weighted Average Exercise Price | $ 95.69 |  |  |
Number Exercisable | 54,282 |  |  |
Exercisable, Weighted Average Exercise Price | $ 95.69 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Beginning outstanding, shares | 54,282 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 2 years 3 months 18 days |  |  |
Weighted Average Exercise Price | $ 95.69 |  |  |
Number Exercisable | 54,282 |  |  |
Exercisable, Weighted Average Exercise Price | $ 95.69 |  |  |
Exercise Price $98.46 |  |  |  |
Text Block [Abstract] |  |  |  |
Beginning outstanding, shares | 133,834 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 2 years 1 month 6 days |  |  |
Weighted Average Exercise Price | $ 98.46 |  |  |
Number Exercisable | 133,834 |  |  |
Exercisable, Weighted Average Exercise Price | $ 98.46 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Beginning outstanding, shares | 133,834 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 2 years 1 month 6 days |  |  |
Weighted Average Exercise Price | $ 98.46 |  |  |
Number Exercisable | 133,834 |  |  |
Exercisable, Weighted Average Exercise Price | $ 98.46 |  |  |
Exercise price $100.77 |  |  |  |
Text Block [Abstract] |  |  |  |
Beginning outstanding, shares | 109,442 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 1 year 1 month 6 days |  |  |
Weighted Average Exercise Price | $ 100.77 |  |  |
Number Exercisable | 109,442 |  |  |
Exercisable, Weighted Average Exercise Price | $ 100.77 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Beginning outstanding, shares | 109,442 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 1 year 1 month 6 days |  |  |
Weighted Average Exercise Price | $ 100.77 |  |  |
Number Exercisable | 109,442 |  |  |
Exercisable, Weighted Average Exercise Price | $ 100.77 |  |  |

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- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option 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)(1)(iii) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option 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)(1)(iii) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 (e)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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