Earnings Per Share (Schedule of Earnings Per Share, Basic And Diluted) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Numerators [Abstract]
Numerator for both basic and diluted EPS, net income	$ 68,566,071	$ 45,430,567
Denominators [Abstract]
Denominator for basic EPS, weighted-average shares outstanding	144,918,406	142,534,655
Potentially dilutive shares resulting from stock plans	1,800,101	540,810
Denominator for diluted EPS	146,718,507	143,075,465
Shares related to stock plans not included in diluted average common shares outstanding because their effect would be anti-dilutive	594,415	5,034,165