Note 9 - Goodwill and Intangible Assets (Details Textual) - USD ($)	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Mar. 02, 2026	Dec. 31, 2025
Goodwill	$ 271,651,000			$ 167,450,000
Intangible Asset, Finite-Lived, Amortization Expense	865,000	$ 735,000
Middlefield Banc Corp [Member]
Goodwill			$ 104,201,000
Goodwill, Acquired During Period	$ 104,200,000

Amount of amortization expense for finite-lived intangible asset. Excludes goodwill and capitalized cost for software to be sold, leased, or marketed.

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+ Details

- Definition

Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

+ References

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+ Details