Balance Sheets - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Cash and equivalents	$ 38,740,543	$ 14,997,613
Marketable securities	356,106,136	421,554,499
Trade receivables, net of reserve	47,865,261	36,575,028
Contract assets, prepaid and other	14,503,565	14,223,037
Current assets	457,215,505	487,350,177
Computer equipment	11,933,654	13,339,425
Furniture and fixtures	75,203,069	76,135,675
Buildings	190,105,517	190,105,517
Land	26,717,577	26,717,577
Accumulated depreciation	140,912,562	138,527,057
Fixed assets	163,047,255	167,771,137
Other assets	7,143,257	7,193,998
Deferred tax assets	7,392,619	7,160,037
Total assets	634,798,636	669,475,349
Accounts payable	626,607	211,391
Taxes payable	7,773,643	3,111,878
Accrued expenses	24,500,858	24,327,709
Deferred revenue	46,284,767	39,711,207
Current liabilities	79,185,875	67,362,185
Deferred tax liabilities	13,662,610	26,951,474
Tax reserves	16,473,255	17,411,282
Total liabilities	109,321,740	111,724,941
Common stock value	37,190,854	37,190,854
Additional paid-in capital	122,907,959	122,907,959
Retained income	365,378,083	397,651,595
Shareholder equity	525,476,896	557,750,408
Total liabilities and shareholder equity	$ 634,798,636	$ 669,475,349