Quarterly report pursuant to Section 13 or 15(d)

Assets and Liabilities Measured at Fair Value (Details)

v3.10.0.1
Assets and Liabilities Measured at Fair Value (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Realized and Unrealized Gains (Losses) on Financial Instruments        
Realized and unrealized gains (losses) $ 5,678 $ 2,675 $ 3,659 $ 5,026
Zero-strike call option        
Realized and Unrealized Gains (Losses) on Financial Instruments        
Realized and unrealized gains (losses) $ 5,678 $ 2,675 $ 3,659 $ 5,026