Financial Highlights (Expense Ratios to Average Equity) (Details) |
3 Months Ended | 9 Months Ended |
|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2018 |
|
| Investment Company, Financial Highlights [Abstract] | ||
| Operating expenses, before interest expense and other investment related expenses | (2.70%) | (2.79%) |
| Investment Company, Incentive Fee to Average Net Assets | (0.07%) | (0.12%) |
| Interest expense and other investment related expenses | (12.97%) | (11.26%) |
| Total Expenses | (15.74%) | (14.17%) |