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Fair Value of Financial Instruments (Narrative) (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Other liabilities | $ 224,877 | $ 229,335
Liabilities fair value | 1,323 | 785
Unsecured Debt [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Liabilities fair value | 375,000 |
Secured Notes One [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Secured loan |  | 120,000
Secured Notes Two [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Secured loan |  | 20,000
Equity Contract [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Liabilities fair value | $ 123 | $ 20

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