Note 1 - Basis of Presentation - (Details Textual)	Mar. 31, 2018
Number of Wealth Solution Offices	1

Represents the number of wealth solution offices in operation.

No definition available.

Name:	bfst_NumberOfWealthSolutionOffices
Namespace Prefix:	bfst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant