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

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Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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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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Note 10 - Leases (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
Note 10 - Leases (Details Textual) - USD ($)	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Mar. 02, 2026	Dec. 31, 2025
Lessee, Operating Lease, Remaining Lease Term (Year)	15 years 9 months 18 days		15 years 9 months 18 days
Operating Lease, Right-of-Use Asset	$ 11,100,000		$ 11,100,000			$ 7,900,000
Operating Lease, Liability	11,409,000		11,409,000			$ 8,200,000
Operating Lease, Expense	$ 594,000	$ 392,000	$ 1,500,000	$ 1,000,000
Operating Lease, Weighted Average Remaining Lease Term (Year)	8 years 8 months 12 days		8 years 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	3.91%		3.91%
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets		Other Assets			Other Assets
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities		Other Liabilities			Other Liabilities
Middlefield Banc Corp [Member]
Operating Lease, Right-of-Use Asset					$ 3,500,000
Operating Lease, Liability					$ 3,500,000
Maximum [Member]
Lessee, Operating Lease, Renewal Term (Year)	15 years		15 years