Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Rental Expense [Abstract]
Rental expense	$ 1,068	$ 1,001	$ 777
Operating lease right of use asset	$ 1,700
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Interest receivable and other assets
Weighted-average remaining lease term	15 years 9 months 18 days
Weighted-average discount rate	3.70%
Future Minimum Rental Commitments Due under Non-Cancelable Operating Leases [Abstract]
2024	$ 646
2025	305
2026	211
2027	118
2028	118
Thereafter	774
Total lease payments	2,172
Less imputed interest	(298)
Operating lease liability	$ 1,874
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	bsvn:InterestPayableAndOtherLiabilitiesMember

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Amount of lessee's undiscounted obligation for lease payment for operating lease.

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Amount of lessee's undiscounted obligation for lease payment for operating lease due after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.

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Amount of operating lease expense. Excludes sublease income.

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Present value of lessee's discounted obligation for lease payments from operating lease.

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Indicates line item in statement of financial position that includes operating lease liability.

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Amount of lessee's right to use underlying asset under operating lease.

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Indicates line item in statement of financial position that includes operating lease right-of-use asset.

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Weighted average discount rate for operating lease calculated at point in time.

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Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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