Unaudited Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 159,933,028	$ 199,957,288
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	50,052,518	51,497,665
(Gain) on disposal of assets	(45,214)	(19,891)
Loss on disposal of assets	11,776	133,036
(Gain) on sale of investments	(391,378)	(969,971)
Loss on sale of investments	989,196	192,346
Change in deferred income taxes	5,044,744	(3,546,862)
Stock-based compensation expense related to employee stock options, employee stock purchases and restricted stock	15,361,567	12,622,158
Change in operating assets and liabilities:
Accounts receivable, net	(24,609,666)	50,784,339
Inventories	(76,310,383)	(37,608,133)
Prepaid expenses and other	(6,035,375)	(41,394,722)
Accounts payable	48,905,968	16,477,865
Accrued liabilities, excluding dividends declared and short-term debt	16,354,262	4,117,051
Net cash provided by operating activities	189,261,043	252,242,169
Activity in available-for-sale securities:
Sales proceeds	37,429,595	34,250,068
Maturities and calls	3,000,000	16,685,000
Purchases	(19,506,446)	(71,596,074)
Purchase of equity method investments	(24,250,000)	0
Plant and equipment additions	(57,998,319)	(31,352,443)
Proceeds from sale of plant and equipment	44,881	99,850
Acquisition of businesses, net of cash acquired	0	(12,023,440)
Increase in other assets	(1,937,117)	(458,637)
Net cash used for investing activities	(63,217,406)	(64,395,676)
CASH FLOWS USED FOR FINANCING ACTIVITIES:
Issuance of common stock from stock plan transactions	8,995,167	13,656,884
Cash dividends paid	(56,725,981)	(58,227,768)
Repurchases of common stock	(71,252,022)	(213,613,842)
Net cash used for financing activities	(118,982,836)	(258,184,726)
NET INCREASE IN CASH AND CASH EQUIVALENTS	7,060,801	(70,338,233)
CASH AND CASH EQUIVALENTS, beginning of period	262,311,670	423,371,036
CASH AND CASH EQUIVALENTS, end of period	$ 269,372,471	$ 353,032,803