Quarterly report pursuant to Section 13 or 15(d)

Bank loans (Details)

v3.22.1
Bank loans (Details)
 1 Months Ended
Aug. 31, 2021
USD ($)
item
Mar. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Jul. 31, 2021
USD ($)
Line of Credit Facility [Line Items]        
Credit facility, outstanding   $ 20,000,000 $ 32,000,000  
Line of credit, interest rate at period end   1.16% 0.80%  
Wells Fargo Credit Facility        
Line of Credit Facility [Line Items]        
Line of credit, borrowing limit $ 400,000,000     $ 250,000,000
Number of six-month extension options | item 2      
Number of twelve-month extension options | item 1      
Line of credit, facility fee 0.10%      
Sustainability-linked pricing component, pricing improvement 0.01%      
Option to increase commitments, additional amount $ 300,000,000      
Payment of deferred financing costs $ 2,200,000      
Unamortized loan origination costs   $ 2,000,000 $ 2,100,000  
Wells Fargo Credit Facility | LIBOR        
Line of Credit Facility [Line Items]        
Variable rate spread 0.70%      
Wells Fargo Credit Facility | Minimum        
Line of Credit Facility [Line Items]        
Line of credit, facility fee 0.10%      
Wells Fargo Credit Facility | Minimum | LIBOR        
Line of Credit Facility [Line Items]        
Variable rate spread 0.70%      
Wells Fargo Credit Facility | Maximum        
Line of Credit Facility [Line Items]        
Line of credit, facility fee 0.25%      
Wells Fargo Credit Facility | Maximum | LIBOR        
Line of Credit Facility [Line Items]        
Variable rate spread 1.35%