Share Based Compensation and Benefit Plans - Narrative (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation [Abstract]
Number of additional shares approved for grant (in shares)	600
Shares issued on deferral basis, credited percentage of current value	90.00%
Share-based payment arrangement, nonvested award, cost not yet recognized, amount	$ 2,300
Share-based payment arrangement, nonvested award, cost not yet recognized, period for recognition	1 year 8 months 26 days
Defined contribution plan, employer matching contribution, percent of match	50.00%	50.00%	50.00%
Defined contribution plan, employer matching contribution, percent of employees' gross pay	8.00%	8.00%	8.00%
Maximum matching contribution, percent	6.00%
Employee stock ownership plan contributions	2.00%	2.00%	2.00%
401(k) and employee stock ownership plans, amount expensed	$ 2,900	$ 3,300	$ 3,200
Performance-based compensation expense	12,700	15,600	15,700
Health care and life insurance expense	6,200	6,100	4,800
Long-Term Incentive Plan
Share Based Compensation [Abstract]
Total compensation expense recognized	1,800	1,600	1,600
Tax benefit relating to compensation expense recognized	$ 400	$ 300	$ 300
Restricted Stock \| Long-Term Incentive Plan
Share Based Compensation [Abstract]
Vesting period	3 years	3 years	3 years
Performance Shares \| Long-Term Incentive Plan
Share Based Compensation [Abstract]
Vesting period	3 years	3 years	3 years
Non-Employee Directors
Share Based Compensation [Abstract]
Number of additional shares approved for grant (in shares)	100
Total compensation expense recognized	$ 400	$ 400	$ 400
Tax benefit relating to compensation expense recognized	$ 80	$ 80	$ 70
Executive Officer \| Restricted Stock \| Long-Term Incentive Plan
Share Based Compensation [Abstract]
Number of restricted stock units issued to executive officers (in shares)	60	90	60
Executive Officer \| Performance Shares \| Long-Term Incentive Plan
Share Based Compensation [Abstract]
Number of restricted stock units issued to executive officers (in shares)	20	20	20
Director
Share Based Compensation [Abstract]
Shares issues as retainer fees (in shares)	20	20	20

Maximum percentage of employee gross pay the employer may contribute to a defined contribution plan.

No definition available.

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- Definition

Expenditures for employee health care and life insurance benefits as provided for compensation.

+ References

No definition available.

+ Details

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

- Definition

This item represents the percentage of contributions during the period made by the entity to the Employee Stock Ownership Plan (ESOP).

+ References

No definition available.

+ Details

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- Definition

Represents the expense recognized during the period arising from compensation arrangements for performance programs with employees, directors and certain consultants qualifying for treatment as employees.

+ References

No definition available.

+ Details

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- Definition

Share issued to directors in place of quarterly cash retainer's fees during the period.

+ References

No definition available.

+ Details

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- Definition

The credited percentage of the current value of shares issued on a deferred basis.

+ References

No definition available.

+ Details

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- Definition

Number of new stock units or restricted shares issued during the period.

+ References

No definition available.

+ Details

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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Balance Type:	debit
Period Type:	duration

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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Balance Type:	debit
Period Type:	duration

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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- Definition

Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

+ References

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- References

No definition available.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

+ Details

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Data Type:	xbrli:durationItemType
Balance Type:	na
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- Definition

Number of additional shares authorized for issuance under share-based payment arrangement.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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- Details

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