Earnings Per Share (Schedule of Earnings Per Share, Basic And Diluted) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerators [Abstract]
Numerator for both basic and diluted EPS, net income	$ 97,556,741	$ 80,279,994
Denominators [Abstract]
Denominator for basic EPS, weighted-average shares outstanding	287,408,900	289,210,621
Potentially dilutive shares resulting from stock plans	4,070,938	2,105,732
Denominator for diluted EPS	291,479,838	291,316,353
Shares related to stock plans not included in diluted average common shares outstanding because their effect would be anti-dilutive	2,311	7,866,330