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Restricted Stock Plan (Details) - Restricted Stock - Isabella Bank Corporation Restricted Stock Plan $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense	$ 4
Minimum [Member]
Share-based Payment Arrangement [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Employee Annual Salary	2500.00%
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Employee Annual Salary	2500.00%
Maximum [Member]
Share-based Payment Arrangement [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Employee Annual Salary	4000.00%
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Employee Annual Salary	4000.00%

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Employee Annual Salary

+ References

No definition available.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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-Section 50
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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