Comprehensive Income (AOCI Rollforward) (Details) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 1,938,087,820	$ 1,861,751,660	$ 2,049,518,261
Other comprehensive income (loss), net of tax	8,140,155	311,235	(2,150,994)
Ending balance	1,963,943,128	1,938,087,820	1,861,751,660
Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			0
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(1,289,103)	(1,600,338)	7,193,383
Ending balance	6,851,052	(1,289,103)	(1,600,338)
Accumulated Other Comprehensive Income (Loss) \| Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(6,642,727)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,384,589)	(1,674,887)	645,030
Other comprehensive income before reclassifications	3,153,634	(709,702)	(2,319,917)
Other comprehensive income (loss), net of tax	3,153,634	(709,702)	(2,319,917)
Ending balance	769,045	(2,384,589)	(1,674,887)
Unrealized gains (losses) on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	1,095,486	74,549	6,626,379
Other comprehensive income before reclassifications	6,644,459	1,403,521	1,675,823
Amounts reclassified from accumulated other comprehensive income	(1,657,938)	(382,584)	(1,584,926)
Other comprehensive income (loss), net of tax	4,986,521	1,020,937	(6,551,830)
Ending balance	6,082,007	1,095,486	74,549
Unrealized gains (losses) on available-for-sale securities \| Cumulative Effect, Period of Adoption, Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(6,642,727)
Unrealized gains (losses) on derivatives:
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	0	0	(78,026)
Other comprehensive income before reclassifications	0	0	175,308
Amounts reclassified from accumulated other comprehensive income	0	0	(97,282)
Other comprehensive income (loss), net of tax	0	0	78,026
Ending balance	$ 0	$ 0	$ 0

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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