Intangible Assets, net - Amortization Expenses (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Finite-Lived Intangible Assets [Line Items] | |||
| Total amortization expenses | $ 2,367 | $ 1,715 | $ 1,541 |
| Tradenames [Member] | |||
| Finite-Lived Intangible Assets [Line Items] | |||
| Total amortization expenses | 330 | 84 | 86 |
| Referral Relationships [Member] | |||
| Finite-Lived Intangible Assets [Line Items] | |||
| Total amortization expenses | 1,512 | 1,153 | 1,028 |
| Non-compete Agreements [Member] | |||
| Finite-Lived Intangible Assets [Line Items] | |||
| Total amortization expenses | $ 525 | $ 478 | $ 427 |