| Goodwill and Intangible Assets - Amortization (Details) - USD ($) $ in Thousands | 12 Months Ended | ||
|---|---|---|---|
| Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | |
| Finite-Lived Intangible Assets [Line Items] | |||
| Amortization of intangible assets | $ 1,057 | $ 1,451 | $ 2,358 | 
| Customer contracts | |||
| Finite-Lived Intangible Assets [Line Items] | |||
| Amortization of intangible assets | 30 | 31 | 184 | 
| Customer relationships | |||
| Finite-Lived Intangible Assets [Line Items] | |||
| Amortization of intangible assets | 973 | 1,244 | 1,809 | 
| Non-compete agreements | |||
| Finite-Lived Intangible Assets [Line Items] | |||
| Amortization of intangible assets | 3 | 42 | 116 | 
| Technology | |||
| Finite-Lived Intangible Assets [Line Items] | |||
| Amortization of intangible assets | 47 | 128 | 238 | 
| Trade names | |||
| Finite-Lived Intangible Assets [Line Items] | |||
| Amortization of intangible assets | $ 4 | $ 6 | $ 11 | 
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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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