Unaudited Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 217,629,700		$ 153,048,925
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	59,747,630		42,334,977
Gain on disposal of assets	(35,000)		0
Loss on disposal of assets	411,129		2,114,241
Gain on sale of investments	(14,964,192)		(15,121,583)
Loss on sale of investments	1,081,164		805,805
Deferred income taxes	225,911		(6,271,382)
Stock-based compensation expense related to employee stock options, employee stock purchases and restricted stock	15,569,999		12,528,264
Excess tax benefits from stock-based compensation	(2,615,892)		(2,275,233)
Change in operating assets and liabilities:
Accounts receivable, net	(43,365,458)		(31,755,237)
Inventories	(15,523,737)		42,523,707
Prepaid expenses and other	(13,414,445)		(12,362)
Accounts payable	12,103,087		7,139,387
Accrued liabilities, excluding dividends declared	10,603,937		18,606,444
Net cash provided by operating activities	227,453,833		223,665,953
Activity in available-for-sale securities:
Sales proceeds	68,958,662		69,937,242
Maturities and calls	0		98,142,408
Purchases	(63,310,363)		(58,278,107)
Plant and equipment additions	(49,994,352)		(38,026,769)
Proceeds from sale of plant and equipment	35,005		316,449
Acquisition of businesses, net of cash acquired	0		(698,107,014)
(Increase) in other assets	(1,213,792)		(602,017)
Net cash used for investing activities	(45,524,840)		(626,617,808)
CASH FLOWS (USED FOR) PROVIDED BY FINANCING ACTIVITIES:
Proceeds from borrowings on Credit Agreement	0		275,000,000
Repayment of long-term debt	(5,625,000)		0
Deferred Financing Costs	0		(953,800)
Issuance of common stock from stock plan transactions	19,184,437		22,526,742
Cash dividends paid	(64,209,453)		(58,898,029)
Repurchases of common stock	(9,999,957)		0
Excess tax benefits from stock-based compensation	2,615,892		2,275,233
Net cash (used for) provided by financing activities	(58,034,081)		239,950,146
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	123,894,912		(163,001,709)
CASH AND CASH EQUIVALENTS, beginning of period	309,591,724	[1]	389,678,664
CASH AND CASH EQUIVALENTS, end of period	$ 433,486,636		$ 226,676,955

[1] Note: The condensed consolidated balance sheet at December 31, 2013 has been derived from the audited 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.