Inventory - Components of Inventory (Detail) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Inventory Disclosure [Abstract] | ||
| Raw materials and purchased parts | $ 62,252 | $ 72,179 |
| Work in process | 4,396 | 5,017 |
| Finished goods and replacement parts | 24,253 | 22,650 |
| Inventories, net | $ 90,901 | $ 99,846 |