Earnings Per Share (Schedule of Earnings Per Share, Basic And Diluted) (Details) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 05, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Numerators [Abstract]
Numerator for both basic and diluted EPS, net income		$ 78,332,425	$ 72,336,883	$ 230,074,303	$ 217,629,700
Denominators [Abstract]
Denominator for basic EPS, weighted-average shares outstanding		292,589,866	290,969,434	293,742,028	290,383,296
Potentially dilutive shares resulting from stock plans		2,787,612	1,906,518	3,252,544	2,353,616
Denominator for diluted EPS		295,377,478	292,875,952	296,994,572	292,736,912
Shares related to stock plans not included in diluted average common shares outstanding because their effect would be anti-dilutive		3,756,369	7,698,848	1,611,900	2,949,114
Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Stock split, conversion ratio	2					2
Stock split, stock dividend	100.00%					100.00%