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Shared-Based Payments (Summary of ESPP and ASPP Shares Issued) (Details) - shares | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Line Items] |  |  |
Stock Issued During Period Shares | 519,863 | 613,678 | 540,337
Employee Stock [Member] |  |  |
Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Line Items] |  |  |
Stock Issued During Period Shares | 99,141 | 72,952 | 70,448
Agent Stock Purchase Plan [Member] |  |  |
Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Line Items] |  |  |
Stock Issued During Period Shares | 69,238 | 47,888 | 41,134

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