Acquired Card Receivables - Summary of Fair Value of Consideration Received from Transfer of Card Receivables (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Dec. 31, 2021	Dec. 31, 2021
Acquired Card Receivables [Abstract]
Cash	$ 366,706	$ 625,207
Beneficial interest derivative	1,093	2,287
Total	$ 367,799	$ 627,494

Initial fair value of consideration received beneficial interest derivative.

No definition available.

Name:	bill_InitialFairValueOfConsiderationReceivedBeneficialInterestDerivative
Namespace Prefix:	bill_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration