Comprehensive Income (Reclassification Out of Accumulated Other Comprehensive Income) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Provision for income taxes	$ (25,804,396)	$ (19,681,661)	$ (42,075,250)	$ (61,633,712)
Amounts Reclassified from Other Comprehensive Income | Unrealized gains (losses) on available-for-sale debt securities
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Realized gain on sale of securities	410,575	374,370	1,361,387	593,351
Provision for income taxes	(86,221)	(78,618)	(285,891)	(124,604)
Total net reclassifications for the period	$ 324,354	$ 295,752	$ 1,075,496	$ 468,747