Quarterly report pursuant to Section 13 or 15(d)

Notes Payable - Additional Information (Details)

v3.20.2
Notes Payable - Additional Information (Details) - USD ($)
1 Months Ended 9 Months Ended
Oct. 01, 2020
Jul. 31, 2020
Sep. 30, 2019
Jan. 31, 2014
Sep. 30, 2020
Sep. 30, 2019
Jun. 30, 2020
Dec. 31, 2019
Jul. 31, 2018
Jul. 31, 2017
Debt Instrument [Line Items]                    
Payment on term loan         $ 77,000,000 $ 29,250,000        
Term Loan | Subsequent Event                    
Debt Instrument [Line Items]                    
Payment on term loan $ 4,300,000                  
Government National Mortgage Association | Revolving Credit Facility                    
Debt Instrument [Line Items]                    
Unused facility fee percentage       70.00%            
Line of credit facility, maximum borrowing capacity             $ 135,000,000.0      
Maximum amount of committed to increase             $ 200,000,000.0      
Outstanding borrowings on credit facility         $ 85,000,000.0     $ 90,000,000.0    
Revolving note expire period         2022-06          
Government National Mortgage Association | LIBOR | Revolving Credit Facility                    
Debt Instrument [Line Items]                    
Line of credit facility, floor rate       4.50%            
Federal Home Loan Mortgage Corporation | Revolving Credit Facility                    
Debt Instrument [Line Items]                    
Unused facility fee percentage   50.00%                
Line of credit facility, maximum borrowing capacity   $ 65,000,000.0             $ 50,000,000.0 $ 25,000,000.0
Outstanding borrowings on credit facility         $ 38,000,000.0     50,000,000.0    
Revolving note expire period   2021-07                
Federal National Mortgage Association | Term Note                    
Debt Instrument [Line Items]                    
Line of credit, outstanding balance     $ 78,000,000.0     78,000,000.0        
Federal National Mortgage Association | New Term Note                    
Debt Instrument [Line Items]                    
Unused facility fee percentage     0.375%              
Line of credit facility, maximum borrowing capacity     $ 150,000,000.0     150,000,000.0        
Outstanding borrowings on credit facility         $ 85,000,000.0     $ 78,000,000.0    
Line of credit, outstanding balance     $ 100,000,000.0     $ 100,000,000.0        
Debt instrument maturity date     Sep. 30, 2022              
Debt instrument periodic payment percentage of principal amount         5.00%          
Federal National Mortgage Association | Federal Funds Rate | New Term Note                    
Debt Instrument [Line Items]                    
Debt instrument variable rate     0.50%              
Federal National Mortgage Association | Eurodollar Base Rate | New Term Note                    
Debt Instrument [Line Items]                    
Debt instrument variable rate     1.00%