Quarterly report pursuant to Section 13 or 15(d)

Borrowings - Additional Information (Details)

v3.21.1
Borrowings - Additional Information (Details)
3 Months Ended 12 Months Ended
Mar. 31, 2021
USD ($)
agreement
debtInstrument
Sep. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Dec. 31, 2020
USD ($)
Feb. 04, 2021
USD ($)
Dec. 10, 2020
USD ($)
Feb. 20, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 05, 2014
USD ($)
Debt Instrument [Line Items]                  
Net cost basis $ 1,048,165,000                
Other income 2,235,000   $ 1,324,000            
Borrowings under lines of credit 100,000     $ 100,000          
Borrowings                  
Debt Instrument [Line Items]                  
Net cost basis $ 1,000,000,000.0                
Weighted average interest rate (as percent) 3.70%   3.98%            
Farm Credit Notes Payable                  
Debt Instrument [Line Items]                  
Interest rate, increase (decrease) (as percent)     28.70% 28.70%          
Basis spread on variable rate, increase (decrease) (as percent)     1.35% 1.35%          
Number of loan agreements | agreement 12                
Other income $ 2,200,000 $ 306,000   $ 2,500,000          
MetLife Facility                  
Debt Instrument [Line Items]                  
Face amount of debt               $ 200,000,000.0  
Maximum borrowing capacity               75,000,000.0  
MetLife Facility | Notes and bonds payables                  
Debt Instrument [Line Items]                  
Face amount of debt 75,000,000           $ 75,000,000.0    
Undrawn commitment $ 38,100,000             $ 21,500,000  
Farmer Mac Facility                  
Debt Instrument [Line Items]                  
Face amount of debt         $ 2,460,000 $ 225,000,000.0     $ 125,000,000.0
Number of bonds | debtInstrument 1                
Mortgage Notes and Bonds Payable | Notes and bonds payables                  
Debt Instrument [Line Items]                  
Fair value amount $ 626,200,000                
Secured debt 632,500,000                
Short Term Mortgage Notes And Bonds Payable | Notes and bonds payables                  
Debt Instrument [Line Items]                  
Borrowings under lines of credit $ 100,000