Segment Reporting - Schedule of Assets by Geographic Segments (Detail) - USD ($) $ in Thousands |
Mar. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Long-lived assets: | ||
| Total | $ 380,411 | $ 380,750 |
| United States [Member] | ||
| Long-lived assets: | ||
| Total | 313,210 | 314,930 |
| United Kingdom [Member] | ||
| Long-lived assets: | ||
| Total | 4,104 | 4,004 |
| Germany [Member] | ||
| Long-lived assets: | ||
| Total | 59,591 | 58,319 |
| Asia (Including Japan) [Member] | ||
| Long-lived assets: | ||
| Total | $ 3,506 | $ 3,497 |