XML 55 R44.htm IDEA: XBRL DOCUMENT v3.10.0.1
Financial Derivatives Narrative (Details) - USD ($)
$ in Thousands
Sep. 30, 2018
Dec. 31, 2017
Derivative [Line Items]    
U.S. Treasury securities sold short, at fair value $ 26,367 $ 81,289
US Treasury Securities [Member]    
Derivative [Line Items]    
U.S. Treasury securities sold short, at fair value 26,367 81,289
Investment Sold, Not yet Purchased, Balance, Principal Amount $ 26,800 $ 82,500