Condensed Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Statement of Comprehensive Income [Abstract] | ||
| Unrecognized actuarial gain, tax | $ 5 | $ 7 |
| Foreign currency translation adjustments, tax | $ 356 | $ 466 |