Unaudited Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 232,589,023	$ 276,617,836
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	73,289,065	75,105,881
(Gain) on disposal of assets	(56,257)	(459,528)
Loss on disposal of assets	22,096	213,430
(Gain) on sale of investments	(391,378)	(969,971)
Loss on sale of investments	1,248,450	192,346
Change in deferred income taxes	4,785,787	(20,269,706)
Stock-based compensation expense related to employee stock options, employee stock purchases and restricted stock	22,973,113	20,114,921
Change in operating assets and liabilities:
Accounts receivable, net	(42,618,585)	43,704,625
Inventories	(102,018,719)	(66,308,038)
Prepaid expenses and other	(16,978,469)	(45,504,501)
Accounts payable	52,511,201	15,748,219
Accrued liabilities, excluding dividends declared and short-term debt	11,002,238	1,195,477
Net cash provided by operating activities	236,357,565	299,380,991
Activity in available-for-sale securities:
Sales proceeds	37,429,595	34,250,068
Maturities and calls	3,500,000	26,110,000
Purchases	(25,304,476)	(86,228,584)
Purchase of equity method investments	(24,250,000)	0
Plant and equipment additions	(108,475,787)	(44,357,786)
Proceeds from sale of plant and equipment	91,949	2,550,805
Acquisition of businesses, net of cash acquired	0	(12,023,440)
Increase in other assets	(2,310,428)	(2,763,847)
Net cash used for investing activities	(119,319,147)	(82,462,784)
CASH FLOWS USED FOR FINANCING ACTIVITIES:
Issuance of common stock from stock plan transactions	12,365,103	20,773,874
Cash dividends paid	(84,941,178)	(86,902,257)
Repurchases of common stock	(83,840,290)	(304,195,755)
Net cash used for financing activities	(156,416,365)	(370,324,138)
NET DECREASE IN CASH AND CASH EQUIVALENTS	(39,377,947)	(153,405,931)
CASH AND CASH EQUIVALENTS, beginning of period	262,311,670	423,371,036
CASH AND CASH EQUIVALENTS, end of period	$ 222,933,723	$ 269,965,105