Nature of Operations and Summary of Significant Accounting Policies, Revenue Recognition (Details)	12 Months Ended
Dec. 31, 2021
Revenue Recognition [Abstract]
Maximum payment period received for transactions	90 days

Payment is typically received in the period the transactions occur.

No definition available.

Name:	bsvn_PaymentPeriodForTransactionsOccur
Namespace Prefix:	bsvn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration