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Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Jul. 01, 2020	Dec. 31, 2019	Oct. 01, 2019	Dec. 31, 2006
Stock Issued During Period, Value, New Issues	$ 106,000	$ 55,000	$ 281,000	$ 161,000
Goodwill, Ending Balance	$ 59,946,000		$ 59,946,000		$ 60,506,000
Valley Ridge Financial Corp. [Member]
Goodwill, Ending Balance									$ 13,700,000
County Bank Corp ("County") [Member]
Goodwill, Ending Balance							$ 38,900,000	$ 38,866,000
Community Shores Bank Corp ("Community Shores") [Member]
Goodwill, Ending Balance					$ 7,300,000	$ 7,353,000
Directors' Stock Purchase Plan [Member]
Stock Issued During Period, Shares, New Issues (in shares)			8,929
Stock Issued During Period, Value, New Issues			$ 247,000
Employee Stock Purchase Plan [Member]
Stock Issued During Period, Shares, New Issues (in shares)			2,957
Stock Issued During Period, Value, New Issues			$ 66,000

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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