Quarterly report pursuant to Section 13 or 15(d)

Significant accounting policies (Schedule of Investment Income) (Details)

v3.7.0.1
Significant accounting policies (Schedule of Investment Income) (Details) - USD ($)
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Interest income $ 22,130 $ 24,530
Realized (losses) (21) (1,151)
Unrealized gains 8,542 26,818
Management fee expenses (4,431) (5,912)
Net investment income $ 26,220 $ 44,285