XML 31 R54.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Concentrations of Credit Risk (Details) - item
6 Months Ended 9 Months Ended
Sep. 30, 2019
Dec. 31, 2019
Concentration Risk [Line Items]    
Number of carriers 2  
Credit Concentration Risk [Member]    
Concentration Risk [Line Items]    
Number of carriers   1