Marketable Investment Securities, Restricted Cash and Other Investment Securities (Details 3) (USD $) In Thousands | Sep. 30, 2011 | Dec. 31, 2010 |
|---|---|---|
| Fair value of marketable investment securities in a loss position | ||
| Total | $ 320,499 | $ 119,135 |
| Less than Six Months | 316,580 | 26,358 |
| Six to Nine Months | 17,566 | |
| Nine Months or More | 3,919 | 75,211 |
| Unrealized loss on marketable investment securities in a loss position | ||
| Less than Six Months | (2,962) | (44) |
| Six to Nine Months | (71) | |
| Nine Months or More | (11) | (118) |
Debt securities | ||
| Fair value of marketable investment securities in a loss position | ||
| Total | 320,499 | 119,135 |
| Less than Six Months | 316,580 | 26,358 |
| Six to Nine Months | 17,566 | |
| Nine Months or More | 3,919 | 75,211 |
| Unrealized loss on marketable investment securities in a loss position | ||
| Less than Six Months | (2,962) | (44) |
| Six to Nine Months | (71) | |
| Nine Months or More | $ (11) | $ (118) |