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Stock-Based Compensation Plans (Details Textual) - USD ($) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014
Stock-based Compensation Plans (Textual) [Abstract] |  |  |  |
Tax benefit realized for the tax deductions |  |  | $ 1,400,000 | $ 1,100,000
Share-based Compensation | $ 4,564,732.65 | $ 4,200,000 | 9,453,000 | 7,886,000
Cash received from employee stock purchase plan purchases |  |  | $ 3,800,000 | $ 3,200,000
2014 Long Term Incentive Plan [Member] |  |  |  |
Stock-based Compensation Plans (Textual) [Abstract] |  |  |  |
Expiry date for stock options grant | May 21, 2024 |  |  |
Shares available for granted under the incentive plan | 1,492,525 |  | 1,492,525 |
Employee Stock Purchase Plan [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Additional Number of Shares Authorized | 1,000,000 |  |  |
Stock-based Compensation Plans (Textual) [Abstract] |  |  |  |
Expiry date for stock options grant |  |  | May 19, 2025 |
Shares available for granted under the incentive plan | 1,464,962 |  | 1,464,962 |
Shares authorized for issuance | 4,500,000 |  | 4,500,000 |
Employee stock purchase price in percentage of fair market value | 85.00% |  |  |
Shares issued to employee under purchase plan | 51,748 | 56,826 |  |
Weighted average fair value of employee stock purchase rights issued | $ 18.12 | $ 14.54 |  |
Maximum [Member] |  |  |  |
Stock-based Compensation Plans (Textual) [Abstract] |  |  |  |
Range Of Forfeiture Provisions |  |  | 5 years |

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- Definition The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 + Details
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