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Summary of Significant Accounting and Reporting Policies (Schedule of Amortized Cost, Unrealized Gains And Losses, And Market Value Of Investment Securities) (Details) - USD ($) | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Long-Term Investments: |  |
Cost | $ 269,889,067 | $ 303,467,531
Unrealized gains | 1,974,255 | 440,807
Unrealized losses | (587,564) | (366,257)
Total | 271,275,758 | 303,542,081
Certificates of Deposit |  |
Short-Term Investments: |  |
Cost | 50,099,795 | 150,299,384
Gains | 0 | 0
Losses | 0 | 0
Market Value | 50,099,795 | 150,299,384
Long-Term Investments: |  |
Cost | 3,500,000 |
Gains | 58,808 |
Losses | (1,010) |
Market Value | 3,557,798 |
Asset-backed Securities |  |
Long-Term Investments: |  |
Cost | 25,971,156 |
Gains | 0 |
Losses | (180,127) |
Market Value | 25,791,029 |
Government Securities |  |
Short-Term Investments: |  |
Cost | 58,343,911 | 9,186,586
Gains | 99,917 | 0
Losses | (11,005) | (10,359)
Market Value | 58,432,823 | 9,176,227
Long-Term Investments: |  |
Cost | 6,012,705 | 56,280,552
Gains | 75,485 | 205,553
Losses | 0 | (2,385)
Market Value | 6,088,190 | 56,483,720
Municipal Bonds |  |
Long-Term Investments: |  |
Cost | 71,997,996 | 17,840,518
Gains | 1,036,116 | 184,914
Losses | (395,422) | 0
Market Value | 72,638,690 | 18,025,432
Corporate Bonds |  |
Short-Term Investments: |  |
Cost | 29,025,624 | 6,981,305
Gains | 194,061 | 0
Losses | 0 | (13,605)
Market Value | 29,219,685 | 6,967,700
Long-Term Investments: |  |
Cost | 22,306,130 | 60,659,498
Gains | 509,868 | 50,340
Losses | 0 | (339,908)
Market Value | 22,815,998 | 60,369,930
Other |  |
Short-Term Investments: |  |
Cost | 2,631,750 | 2,219,688
Gains | 0 | 0
Losses | 0 | 0
Market Value | $ 2,631,750 | 2,219,688
Common Stocks |  |
Long-Term Investments: |  |
Cost |  | 0
Gains |  | 0
Losses |  | 0
Market Value |  | $ 0

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