UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' INVESTMENT - USD ($)	3 Months Ended
	Mar. 31, 2024		Mar. 31, 2023
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 2,312,517,069	[1]	$ 2,065,792,821
Issuance of common stock from stock plan transactions	$ 16,833,986		5,956,022
Repurchases of common stock (in shares)	(1,200,000)
Repurchases of common stock	$ (43,039,087)		(28,462,632)
Stock-based compensation expense related to stock options, employee stock purchases and restricted stock	10,473,792		8,519,535
Dividends declared	(27,743,481)		(28,046,798)
Net income	108,230,714		97,578,261
Other comprehensive loss	(909,204)		1,918,437
Ending Balance	$ 2,376,363,789		$ 2,123,255,646
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	231,455,443		234,169,335
Beginning Balance	$ 13,887,326		$ 14,050,160
Issuance of common stock from stock plan transactions (in shares)	944,345		603,636
Issuance of common stock from stock plan transactions	$ 56,661		$ 36,218
Repurchases of common stock (in shares)	(1,200,903)		(1,046,926)
Repurchases of common stock	$ (72,054)		$ (62,815)
Ending balance (in shares)	231,198,885		233,726,045
Ending Balance	$ 13,871,933		$ 14,023,563
Additional  Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	968,245,875		917,499,323
Issuance of common stock from stock plan transactions	16,777,325		5,919,804
Repurchases of common stock	(4,443,340)		(3,653,772)
Stock-based compensation expense related to stock options, employee stock purchases and restricted stock	10,473,792		8,519,535
Ending Balance	991,053,652		928,284,890
Retained  Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	1,336,940,990		1,148,386,272
Repurchases of common stock	(38,523,693)		(24,746,045)
Dividends declared	(27,743,481)		(28,046,798)
Net income	108,230,714		97,578,261
Ending Balance	1,378,904,530		1,193,171,690
Accumulated  Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(6,557,122)		(14,142,934)
Other comprehensive loss	(909,204)		1,918,437
Ending Balance	$ (7,466,326)		$ (12,224,497)

[1] The condensed consolidated balance sheet at December 31, 2023 has been derived from the audited consolidated financial statements at that date, but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.