Financial Highlights (Expense Ratios to Average Equity) (Details) |
3 Months Ended |
|---|---|
Mar. 31, 2018 | |
| Investment Company, Financial Highlights [Abstract] | |
| Operating expenses, before interest expense and other investment related expenses | (2.67%) |
| Interest expense and other investment related expenses | (9.56%) |
| Total Expenses | (12.23%) |