XML 46 R40.htm IDEA: XBRL DOCUMENT v3.22.2.2
Accounts receivable, unbilled revenue (contract assets) and unearned revenue or payments on account (contract liabilities) - Narrative (Details) - USD ($)
$ in Thousands
 9 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Increase in unbilled services (unbilled revenue) $ 271,170  
Decrease in unearned revenue (payments on account) (71,199)  
Increase in net balance 199,971  
Revenue, remaining performance obligation $ 13,500,000 $ 13,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-10-01    
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]    
Revenue, remaining performance obligation percentage 49.00%  
Revenue, remaining performance obligation, expected timing of satisfaction, period 12 months