Unaudited Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 206,733,664	$ 159,933,028
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	48,841,936	50,052,518
(Gain) on disposal of assets	(214,593)	(45,214)
Loss on disposal of assets	220,568	11,776
(Gain) on sale of investments and equity method investment income	(2,747,586)	(391,378)
Loss on sale of investments and equity method investment losses	4,201,138	989,196
Change in deferred income taxes	(5,122,661)	5,044,744
Stock-based compensation expense related to employee stock options, employee stock purchases and restricted stock	18,264,205	15,361,567
Change in operating assets and liabilities:
Accounts receivable, net	(73,915,719)	(24,609,666)
Inventories	14,334,001	(76,310,383)
Prepaid expenses and other	(2,722,437)	(6,035,375)
Accounts payable	22,410,431	48,905,968
Accrued liabilities, excluding dividends declared	11,483,186	16,354,262
Net cash provided by operating activities	241,766,133	189,261,043
Activity in available-for-sale securities:
Sales proceeds	21,523,990	37,429,595
Maturities and calls	11,650,000	3,000,000
Purchases	(65,945,596)	(43,756,446)
Plant and equipment additions	(90,277,995)	(57,998,319)
Proceeds from sale of plant and equipment	140,610	44,881
Increase in other assets	(3,486,284)	(1,937,117)
Net cash used for investing activities	(126,395,275)	(63,217,406)
CASH FLOWS USED FOR FINANCING ACTIVITIES:
Issuance of common stock from stock plan transactions	13,882,810	8,995,167
Cash dividends paid	(56,146,939)	(56,725,981)
Repurchases of common stock	(54,195,766)	(71,252,022)
Net cash used for financing activities	(96,459,895)	(118,982,836)
NET INCREASE IN CASH AND CASH EQUIVALENTS	18,910,963	7,060,801
CASH, CASH EQUIVALENTS, and RESTRICTED CASH, beginning of period	218,754,638	262,311,670
CASH, CASH EQUIVALENTS, and RESTRICTED CASH, end of period	$ 237,665,601	$ 269,372,471