ACCOUNTING POLICIES, Capitalized Mortgage Loan Servicing Rights (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Mortgage Loan Servicing Rights [Abstract]
Mortgage loan servicing fees	$ 7.9	$ 6.9	$ 6.2

Fees from servicing mortgage loans that have been sold.

No definition available.

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Namespace Prefix:	ibcp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration