Investments and fair value measurements - Debt Securities Held to Maturity Allowance for Credit Loss (Details)
$ in Thousands
3 Months Ended
Mar. 31, 2022
USD ($)
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]  
Beginning balance, January 1, 2022 $ 0
Current-period provision (reduction) for expected credit losses (17)
Write-off charged against the allowance, if any 0
Recoveries of amounts previously written off, if any 0
Ending balance of the allowance for credit losses, March 31, 2022 $ 382