Fair Value Measurements (Investment and Derivative Information) (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Fair Value Measurements | ||
| Liabilities, Fair Value | $ 0 | $ 0 |
| Foreign exchange contracts | Other income expense, net | Not designated as hedging instrument | ||
| Fair Value Measurements | ||
| Foreign exchange forward contracts | $ 418 | $ 200 |
| Minimum | ||
| Fair Value Measurements | ||
| Maturity period of long-term investments | 1 year | |
| Maximum | ||
| Fair Value Measurements | ||
| Maturity period of long-term investments | 2 years | |