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Stock-Based Compensation Plan (Schedule of Stock Option Activity) (Details) (USD $)
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6 Months Ended | |
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Jun. 30, 2014
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Jun. 30, 2013
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| Number of Options Outstanding | ||
| Shares under option at January 1, 2014 | 2,007,433 | |
| Granted | 48,534 | |
| Exercised | (224,258) | (647,667) |
| Forfeited | (23,444) | |
| Shares under option at June 30, 2014 | 1,808,265 | |
| Shares exercisable under option at June 30, 2014 | 1,015,343 | |
| Weighted Average Exercise Price | ||
| Shares under option at January 1, 2014 | $ 29.66 | |
| Granted | $ 93.74 | |
| Exercised | $ 10.49 | |
| Forfeited | $ 48.16 | |
| Shares under option at June 30, 2014 | $ 33.52 | |
| Shares exercisable under option at June 30, 2014 | $ 17.12 | |
| X | ||||||||||
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- Details
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- Definition
The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Net number of share options (or share units) granted during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Number of options outstanding, including both vested and non-vested options. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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| X | ||||||||||
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- Definition
Weighted average price at which option holders acquired shares when converting their stock options into shares. No definition available.
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- Definition
Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated. No definition available.
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- Definition
Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options. No definition available.
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| X | ||||||||||
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- Definition
Number of share options (or share units) exercised during the current period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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