Quarterly report pursuant to Section 13 or 15(d)

Borrowings - Additional Information (Details)

v3.20.2
Borrowings - Additional Information (Details)
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2020
USD ($)
Agreement
debt_instrument
Mar. 31, 2020
USD ($)
Sep. 30, 2019
USD ($)
Sep. 30, 2020
USD ($)
Agreement
debt_instrument
Sep. 30, 2019
USD ($)
Dec. 31, 2019
USD ($)
Feb. 20, 2020
USD ($)
Jan. 10, 2020
USD ($)
Dec. 05, 2014
USD ($)
Debt Instrument [Line Items]                  
Net cost basis $ 860,790,000     $ 860,790,000          
Other income 323,000   $ 62,000 1,668,000 $ 937,000        
Borrowings under lines of credit 11,600,000     11,600,000   $ 100,000      
Borrowings                  
Debt Instrument [Line Items]                  
Net cost basis $ 827,700,000     $ 827,700,000          
Weighted average interest rate (as percent) 4.03%   4.03% 3.99% 3.97%        
Farm Credit Notes Payable                  
Debt Instrument [Line Items]                  
Interest rate, increase (decrease) (as percent)   20.40%       20.40%      
Basis spread on variable rate, increase (decrease) (as percent)   0.98%              
Number of loan agreements | Agreement 10     10          
Other income $ 306,000 $ 1,300,000              
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     $ 75,000,000.0    
Undrawn commitment $ 75,000,000     $ 75,000,000   $ 21,500,000      
Farmer Mac Facility                  
Debt Instrument [Line Items]                  
Face amount of debt               $ 8,100,000 $ 125,000,000.0
Number of bonds | debt_instrument 1     1          
Extinguishment of debt, amount       $ 8,100,000          
Mortgage Notes and Bonds Payable | Notes and bonds payables                  
Debt Instrument [Line Items]                  
Fair value amount $ 497,400,000     497,400,000          
Secured debt 495,100,000     495,100,000          
Short Term Mortgage Notes And Bonds Payable | Notes and bonds payables                  
Debt Instrument [Line Items]                  
Borrowings under lines of credit $ 11,600,000     $ 11,600,000