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Earnings Per Share (Schedule of Earnings Per Share, Basic And Diluted) (Details) - USD ($) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2017 | Jun. 30, 2016
Numerators [Abstract] |  |  |  |
Numerator for both basic and diluted EPS, net income | $ 88,535,947 | $ 86,485,242 | $ 186,092,688 | $ 166,765,236
Denominators [Abstract] |  |  |  |
Denominator for basic EPS, weighted-average shares outstanding | 286,722,482 | 288,803,045 | 286,956,367 | 288,943,030
Potentially dilutive shares resulting from stock plans | 3,120,420 | 2,660,838 | 3,581,875 | 2,429,695
Denominator for diluted EPS | 289,842,902 | 291,463,883 | 290,538,242 | 291,372,725
Shares related to stock plans not included in diluted average common shares outstanding because their effect would be anti-dilutive | 873,937 | 4,330,316 | 109,597 | 6,563,404

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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
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