v3.19.2
Investments - Restricted Cash and Cash Equivalents and Investments (Details) - USD ($)
$ in Thousands
Jun. 30, 2019
Dec. 31, 2018
Jun. 30, 2018
Restricted Cash and Investments Items [Line Items]      
Restricted cash $ 381,698 $ 130,148 $ 130,259
Restricted investments 2,492,232 3,893,811  
Restricted cash and investments 2,873,930 4,023,959  
Liability for investments purchased 298,939 0  
Amortized cost 2,942,207 4,125,661  
Third party agreements      
Restricted Cash and Investments Items [Line Items]      
Restricted cash 21,299 21,420  
Restricted investments 69,999 89,596  
Amortized cost 69,855 88,841  
Related party agreements      
Restricted Cash and Investments Items [Line Items]      
Restricted cash 360,399 108,728  
Restricted investments 2,689,179 3,804,215  
Amortized cost 2,655,683 3,870,731  
Investments Purchased for Related Party Agreements      
Restricted Cash and Investments Items [Line Items]      
Restricted investments – liability for investments purchased for related party agreements $ (266,946) $ 0