Annual report pursuant to Section 13 and 15(d)

Bank Loans (Narrative) (Details)

v3.22.0.1
Bank Loans (Narrative) (Details)
12 Months Ended
Dec. 31, 2021
USD ($)
item
Jul. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Line of Credit Facility [Line Items]      
Payment of deferred financing costs $ 2,248,000    
Wells Fargo Credit Facility [Member]      
Line of Credit Facility [Line Items]      
Line of credit, borrowing limit $ 400,000,000.0 $ 250,000,000.0  
Number of six-month extension options | item 2    
Number of twelve-month extension options | item 1    
Spread over LIBOR 0.70%    
Line of credit, facility fee percent 0.10%    
Sustainability-linked pricing component, pricing improvement percentage 0.01%    
Option to increase commitments, additional amount $ 300,000,000.0    
Credit facility, outstanding $ 32,000,000.0   $ 0
Credit Facility, interest rate 0.80%    
Payment of deferred financing costs $ 2,200,000    
Unamortized loan origination costs $ 2,100,000   $ 200,000
Wells Fargo Credit Facility [Member] | Minimum [Member]      
Line of Credit Facility [Line Items]      
Spread over LIBOR 0.70%    
Line of credit, facility fee percent 0.10%    
Wells Fargo Credit Facility [Member] | Maximum [Member]      
Line of Credit Facility [Line Items]      
Spread over LIBOR 1.35%    
Line of credit, facility fee percent 0.25%