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Stock-Based Compensation (Narrative) (Details) (USD $)
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3 Months Ended | |
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Mar. 31, 2012
Y
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Mar. 31, 2011
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Restricted Stock Units [Member]
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| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] | ||
| Unrecognized costs related to share based compensation | $ 13,345,000 | |
| Weighted average period of recognition of unrecognized costs related to stock options, years | 2.80 | |
| Restricted stock units granted | 149,691 | 122,235 |
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Stock Option [Member]
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| Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] | ||
| Stock options granted | 323,615 | 314,701 |
| Unrecognized costs related to share based compensation | $ 8,266,000 | |
| Weighted average period of recognition of unrecognized costs related to stock options, years | 2.83 | |
| X | ||||||||||
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- Definition
As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, using a decimal to express in number of years. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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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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- Details
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