| Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
| Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | |
| Share-based Compensation [Abstract] | ||||
| Stock-based compensation expense | $ 3,200 | $ 3,400 | $ 6,700 | $ 7,700 | 
| Capitalized stock-based compensation | 1,300 | $ 1,300 | 2,694 | $ 3,066 | 
| Unrecognized compensation expense | $ 15,400 | $ 15,400 | ||
| Weighted average period | 1 year 6 months 7 days | |||
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- Definition Non-cash stock based compensation capitalized. No definition available. 
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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Unrecognized cost of unvested share-based compensation awards. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- References No definition available. 
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