Long-Term Debt (Wells Fargo Note Payable) (Details)  | 
9 Months Ended | 
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Sep. 30, 2018  | |
| Wells Fargo Note Payable | LIBOR | |
| Debt Instrument [Line Items] | |
| Variable interest rate | 2.25% | 
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- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. No definition available. 
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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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