Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Number of Operating Segments	1
Net Cash Provided by (Used in) Investing Activities, Total	$ (268,636)	$ (184,264)
Time Deposit, Maturity (Year)	7 years
Other than Temporary Impairment Losses, Investments, Total	$ 0
Goodwill, Impairment Loss	$ 0	0
Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)	3 years
Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)	7 years
Building [Member] \| Minimum [Member]
Property, Plant and Equipment, Useful Life (Year)	15 years
Building [Member] \| Maximum [Member]
Property, Plant and Equipment, Useful Life (Year)	40 years
Interest-bearing Deposits and Federal Funds Sold Reclassified as Cash and Cash Equivalents [Member]
Net Cash Provided by (Used in) Investing Activities, Total		$ (61,000)

The maturity of time deposits.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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