Statements of Shareholder Equity - USD ($)	Total	Common Stock Paid-in capital	Retained income	Other Comprehensive
Balance at Dec. 31, 2016	$ 523,534,697	$ 160,098,813	$ 317,019,791	$ 46,416,093
Net revenue recognition standard adjustment	(12,580,916)		(12,580,916)
Net income	77,428,576		77,428,576
Change in unrealized after-tax security gains	779,211			779,211
Dividends paid	(92,233,318)		(92,233,318)
Balance at Dec. 31, 2017	496,928,250	160,098,813	289,634,133	47,195,304
Net income	56,205,796		56,205,796
Dividends paid	(92,233,318)		(92,233,318)
Cumulative effect of accounting change			47,195,304	$ (47,195,304)
Balance at Dec. 31, 2018	460,900,728	160,098,813	300,801,915
Net income	180,157,193		180,157,193
Dividends paid	(83,307,513)		(83,307,513)
Balance at Dec. 31, 2019	$ 557,750,408	$ 160,098,813	$ 397,651,595