Description of the Business and Summary of Significant Accounting Policies - Recent Developments (Details) $ in Millions	Feb. 27, 2026 USD ($)
Description of the Business and Summary of Significant Accounting Policies
Aggregate gross sale price	$ 50.0
Distribution agent commission, percentage	2.50%

Value of commission entitled to be received by the distribution agent under the offering calculated as percentage of gross sale price.

No definition available.

Name:	bwb_DistributionAgentCommissionPercentage
Namespace Prefix:	bwb_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant