Fair Value Measurement - Fair Value of Assets (Liabilities) Not Measured at Fair Value In Consolidated Balance Sheets (Details) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
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|---|---|---|---|---|---|---|---|
| Debt Securities | Level 1 | |||||||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||||||
| Fair value | [1] | $ 0 | $ 0 | ||||
| Debt Securities | Level 2 | |||||||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||||||
| Fair value | [1] | 0 | 0 | ||||
| Debt Securities | Level 3 | |||||||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||||||
| Fair value | [1] | 20,519 | 22,226 | ||||
| Long-term Debt | Level 1 | |||||||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||||||
| Long term debt, fair value | [2] | 0 | 0 | ||||
| Long-term Debt | Level 2 | |||||||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||||||
| Long term debt, fair value | [2] | (368,408) | (395,618) | ||||
| Long-term Debt | Level 3 | |||||||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||||||
| Long term debt, fair value | [2] | $ 0 | $ 0 | ||||
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