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Stock-Based Compensation Plans (Details Textual) (USD $) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2014 | Sep. 30, 2013
Additional Stock-based Compensation Plans (Textual) [Abstract] |  |  |  |
Cash received from option exercises and employee stock purchase plan purchases |  |  | $ 4,700,000 | $ 4,400,000
Tax benefit realized for the tax deductions |  |  | 1,100,000 | 1,400,000
Share-based Compensation | $ 4,000,000 | $ 3,500,000 | $ 11,871,000 | $ 10,473,000
2007 Long Term Incentive Plan [Member] |  |  |  |
Stock-based Compensation Plans (Textual) [Abstract] |  |  |  |
Maximum number of shares available for issuance under the plan | 7,500,000 |  | 7,500,000 |
2014 Long Term Incentive Plan [Member] |  |  |  |
Stock-based Compensation Plans (Textual) [Abstract] |  |  |  |
Maximum number of shares available for issuance under the plan | 1,200,000 |  | 1,200,000 |
Expiry date for stock options grant | May 21, 2024 |  |  |
Shares available for granted under the incentive plan | 1,750,584 |  | 1,750,584 |
Employee Stock Purchase Plan [Member] |  |  |  |
Stock-based Compensation Plans (Textual) [Abstract] |  |  |  |
Expiry date for stock options grant |  |  | Mar. 06, 2016 |
Shares authorized for issuance | 3,500,000 |  | 3,500,000 |
Employee stock purchase price in percentage of fair market value | 85.00% |  |  |
Shares remaining in reserve for future issuance | 539,026 |  | 539,026 |
Shares issued to employee under purchase plan | 80,938 | 83,698 |  |
Weighted average fair value of employee stock purchase rights issued | $ 15.07 | $ 13.65 |  |
Maximum [Member] |  |  |  |
Stock-based Compensation Plans (Textual) [Abstract] |  |  |  |
Range Of Forfeiture Provisions |  |  | 5 years |

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- Definition Employee service share based compensation tax benefit realized from exercise of stock options and vesting of restricted shares. + References No definition available. + Details
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- Definition Employee common stock purchase price in percentage of fair market value. + References No definition available. + Details
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- Definition Maximum number of shares available for issuance under the plan. + References No definition available. + Details
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- Definition The total cash inflow associated with the amount received from employees to purchase company stock, including stock option exercises. + References No definition available. + Details
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- Definition Shares remaining in reserve for future issuance. + References No definition available. + Details
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- Definition Weighted average fair value of employee stock purchase rights issued. + References No definition available. + Details
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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=31042434&loc=d3e3602-108585 + Details
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- Definition Date the equity-based award expires, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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