Statements of Income and Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Product revenue	$ 161,975,285	$ 165,487,109	$ 154,802,239
Service revenue	331,869,347	322,701,637	326,101,656
Total revenue	493,844,632	488,188,746	480,903,895
Operations, development	332,551,702	334,612,704	328,502,568
Selling, G & A	96,813,268	88,808,769	88,420,193
Operating expense	429,364,970	423,421,473	416,922,761
Operating income	64,479,662	64,767,273	63,981,134
Other income	21,463,262	25,980,379	38,622,542
Gain on sale of property	88,948,907	0	0
Change in unrealized security gains	57,809,294	(23,416,834)	0
Other expense	6,112,326	7,124,656	6,117,897
Pretax income	226,588,799	60,206,162	96,485,779
State income tax (benefit)	7,623,403	(387,076)	3,535,566
Federal income tax	38,808,203	4,387,442	15,521,637
Income tax	46,431,606	4,000,366	19,057,203
Net income	$ 180,157,193	$ 56,205,796	77,428,576
Change in unrealized after-tax security gains			779,211
Comprehensive income			$ 78,207,787