General form of registration statement for all companies including face-amount certificate companies

Concentration of credit risk and off-balance sheet risk (Q3) (Details)

v3.20.4
Concentration of credit risk and off-balance sheet risk (Q3) (Details)
9 Months Ended 12 Months Ended
Sep. 30, 2020
Dec. 31, 2019
Sep. 30, 2020
Dec. 31, 2019
Dec. 31, 2018
Revenues          
Concentration Risk [Line Items]          
Concentration risk percentage       10.00% 10.00%
Revenues | Customer concentration risk | Two customers          
Concentration Risk [Line Items]          
Concentration risk percentage     35.00%    
Accounts receivable          
Concentration Risk [Line Items]          
Concentration risk percentage       44.00% 68.00%
Accounts receivable | Customer concentration risk | Three customers          
Concentration Risk [Line Items]          
Concentration risk percentage 70.00%        
Accounts receivable | Customer concentration risk | One customer          
Concentration Risk [Line Items]          
Concentration risk percentage   44.00%