Quarterly report pursuant to Section 13 or 15(d)

Credit facilities - Schedule of Additional Detail on Credit Facility (Details)

v3.10.0.1
Credit facilities - Schedule of Additional Detail on Credit Facility (Details) - USD ($)
$ in Thousands
Sep. 30, 2018
Dec. 31, 2017
Line of Credit Facility [Line Items]    
Outstanding balance $ 289,293 $ 69,922
Senior Secured Revolving Credit Facility [Member]    
Line of Credit Facility [Line Items]    
Outstanding balance 252,000 70,000
Value of collateral pledged to credit facility $ 362,000 $ 252,000
Weighted average short-term borrowing rate 3.80% 3.00%