|
Fair Value Measurements (Details) (USD $)
In Thousands, unless otherwise specified |
Dec. 31, 2013
|
Dec. 31, 2012
|
|---|---|---|
| Fair Value Measurements | ||
| Amount of transfers of financial assets between Level 1 and Level 2 measures | $ 0 | |
| Assets: | ||
| Short term investments: | 117,218 | 200,577 |
| Total short-term investments | 117,200 | |
|
Available-for-sale equity securities
|
||
| Assets: | ||
| Short term investments: | 96,942 | 174,610 |
|
Recurring
|
||
| Assets: | ||
| Total short-term investments | 117,218 | |
|
Recurring | Available-for-sale equity securities
|
||
| Assets: | ||
| Short term investments: | 96,942 | |
|
Recurring | Corporate debt securities
|
||
| Assets: | ||
| Short term investments: | 19,388 | |
|
Recurring | Mortgage-backed debt securities
|
||
| Assets: | ||
| Short term investments: | 210 | |
|
Recurring | Mortgage-CMO debt securities
|
||
| Assets: | ||
| Short term investments: | 20 | |
|
Recurring | Asset-backed debt securities
|
||
| Assets: | ||
| Short term investments: | 658 | |
|
Recurring | Level 1
|
||
| Assets: | ||
| Total short-term investments | 96,738 | |
|
Recurring | Level 1 | Available-for-sale equity securities
|
||
| Assets: | ||
| Short term investments: | 96,080 | |
|
Recurring | Level 1 | Asset-backed debt securities
|
||
| Assets: | ||
| Short term investments: | 658 | |
|
Recurring | Level 2
|
||
| Assets: | ||
| Total short-term investments | 20,480 | |
|
Recurring | Level 2 | Available-for-sale equity securities
|
||
| Assets: | ||
| Short term investments: | 862 | |
|
Recurring | Level 2 | Corporate debt securities
|
||
| Assets: | ||
| Short term investments: | 19,388 | |
|
Recurring | Level 2 | Mortgage-backed debt securities
|
||
| Assets: | ||
| Short term investments: | 210 | |
|
Recurring | Level 2 | Mortgage-CMO debt securities
|
||
| Assets: | ||
| Short term investments: | $ 20 |