Investments (Schedule of Amortized Cost, Unrealized Gains and Losses, and Market Value of Investment Securities) (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Cost	$ 193,928,063	$ 177,467,550
Unrealized Gains	6,971,159	8,260,042
Unrealized Losses	(2,686,086)	(561,300)
Market Value	198,213,136	185,166,292
Short-Term Investments \| Certificate of Deposit
Debt Securities, Available-for-sale [Line Items]
Cost	1,502,822	1,502,187
Unrealized Gains	10,107	14,506
Unrealized Losses	(1,552)	0
Market Value	1,511,377	1,516,693
Short-Term Investments \| Corporate Bonds
Debt Securities, Available-for-sale [Line Items]
Cost	2,013,237	7,084,638
Unrealized Gains	7,043	70,962
Unrealized Losses	0	0
Market Value	2,020,280	7,155,600
Short-Term Investments \| Government Securities
Debt Securities, Available-for-sale [Line Items]
Cost	601,784	6,635,132
Unrealized Gains	232	43,318
Unrealized Losses	0	0
Market Value	602,016	6,678,450
Short-Term Investments \| Municipal Bonds
Debt Securities, Available-for-sale [Line Items]
Cost	7,926,891	10,160,376
Unrealized Gains	24,621	124,389
Unrealized Losses	0	0
Market Value	7,951,512	10,284,765
Short-Term Investments \| Other
Debt Securities, Available-for-sale [Line Items]
Cost	1,713,642	1,528,861
Unrealized Gains	0	0
Unrealized Losses	0	0
Market Value	1,713,642	1,528,861
Long-Term Investments \| Asset Backed Securities
Debt Securities, Available-for-sale [Line Items]
Cost	29,690,643	37,681,113
Unrealized Gains	69,718	800,802
Unrealized Losses	(585,461)	(557,378)
Market Value	29,174,900	37,924,537
Long-Term Investments \| Certificate of Deposit
Debt Securities, Available-for-sale [Line Items]
Cost	2,502,449	3,503,898
Unrealized Gains	97,511	141,622
Unrealized Losses	0	0
Market Value	2,599,960	3,645,520
Long-Term Investments \| Corporate Bonds
Debt Securities, Available-for-sale [Line Items]
Cost	27,724,234	8,595,020
Unrealized Gains	362,001	429,015
Unrealized Losses	(119,737)	0
Market Value	27,966,498	9,024,035
Long-Term Investments \| Government Securities
Debt Securities, Available-for-sale [Line Items]
Cost	35,656,412
Unrealized Gains	90,333
Unrealized Losses	(7,919)
Market Value	35,738,826
Long-Term Investments \| Municipal Bonds
Debt Securities, Available-for-sale [Line Items]
Cost	84,595,949	100,776,325
Unrealized Gains	6,309,593	6,635,428
Unrealized Losses	(1,971,417)	(3,922)
Market Value	$ 88,934,125	$ 107,407,831

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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