Balance Sheets - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Cash and equivalents	$ 22,890,472	$ 14,997,613
Marketable securities	336,356,855	421,554,499
Trade receivables, net of reserve	41,239,997	36,575,028
Contract assets, prepaid and other	20,055,945	14,223,037
Current assets	420,543,269	487,350,177
Computer equipment	14,251,552	13,339,425
Furniture and fixtures	76,256,707	76,135,675
Buildings	190,105,517	190,105,517
Land	26,717,577	26,717,577
Accumulated depreciation	141,657,470	138,527,057
Fixed assets	165,673,883	167,771,137
Other assets	7,174,387	7,193,998
Deferred tax assets	7,205,150	7,160,037
Total assets	600,596,689	669,475,349
Accounts payable	702,269	211,391
Taxes payable	4,995,831	3,111,878
Accrued expenses	19,510,726	24,327,709
Deferred revenue	38,317,161	39,711,207
Current liabilities	63,525,987	67,362,185
Deferred tax liabilities	8,914,306	26,951,474
Tax reserves	16,963,034	17,411,282
Total liabilities	89,403,327	111,724,941
Common stock value	37,190,854	37,190,854
Additional paid-in capital	122,907,959	122,907,959
Retained income	351,094,549	397,651,595
Shareholder equity	511,193,362	557,750,408
Total liabilities and shareholder equity	$ 600,596,689	$ 669,475,349