Other Intangible Assets, Net - Other Intangible Assets (Details) - USD ($) $ in Thousands |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Amount | $ 9,680 | $ 6,058 |
| Accumulated Amortization | (5,329) | (4,017) |
| Net Book Value | 4,351 | 2,041 |
| Customer and Contractual Relationships | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Amount | 2,135 | 1,994 |
| Accumulated Amortization | (1,764) | (1,466) |
| Net Book Value | 371 | 528 |
| Internal-Use Software | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Amount | 7,545 | 4,064 |
| Accumulated Amortization | (3,565) | (2,551) |
| Net Book Value | $ 3,980 | $ 1,513 |