ACCOUNTING POLICIES, Bank Owned Life Insurance (Details)	Dec. 31, 2021 Employee
Bank Owned Life Insurance [Abstract]
Number of lives of group flexible premium non-participating variable life insurance contract	260

Number of lives of group flexible premium non-participating variable life insurance contract that the company purchased.

No definition available.

Name:	ibcp_GroupFlexiblePremiumNonParticipatingVariableLifeInsuranceContract
Namespace Prefix:	ibcp_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant