Income classified as other excluding interest income.

No definition available.

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

- Definition

The number of real estate assets financed by the entity sold during the period.

+ References

No definition available.

+ Details

Name:	ibcp_NumberOfRealEstateAssetsSold
Namespace Prefix:	ibcp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of the entity's revenue excluded from the scope of ASU 2014-09.

+ References

No definition available.

+ Details

Name:	ibcp_PercentageOfRevenueExcludedFromASU201409
Namespace Prefix:	ibcp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Earnings on or other increases in the value of the cash surrender value of bank owned life insurance policies.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13)
-URI http://asc.fasb.org/extlink&oid=116637391&loc=SL114874048-224260

+ Details

Name:	us-gaap_BankOwnedLifeInsuranceIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Section 45
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-Publisher FASB
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-Topic 606
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130533-203044

+ Details

Name:	us-gaap_ContractWithCustomerAssetNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
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-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130531-203044

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-Publisher FASB
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-Publisher FASB
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-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118944033&loc=SL49130532-203044

+ Details

Name:	us-gaap_ContractWithCustomerLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_DisaggregationOfRevenueAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of revenue earned, classified as other, excluding interest income.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 1
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(4))
-URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263

+ Details

Name:	us-gaap_NoninterestIncomeOtherOperatingIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
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-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

+ Details

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	srt_ProductOrServiceAxis=ibcp_ServiceChargesOnDepositsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ibcp_OverdraftFeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=ibcp_CustomerRetailMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=ibcp_CustomerBusinessMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ibcp_AccountServiceChargesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ibcp_OtherDepositRelatedIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ibcp_ATMFeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ibcp_OtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ibcp_InterchangeIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ibcp_InvestmentAndInsuranceCommissionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ibcp_AssetManagementRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ProductOrServiceAxis=ibcp_TransactionBasedRevenueMember
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Revenue from Contracts with Customers (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) Asset	Sep. 30, 2018 USD ($) Asset	Sep. 30, 2019 USD ($) Asset	Sep. 30, 2018 USD ($) Asset	Dec. 31, 2018 USD ($)
Revenue from Contracts with Customers [Abstract]
Percentage of revenues excluded from ASC Topic 606	84.70%	83.10%	84.70%	83.10%
Contract assets	$ 0		$ 0		$ 0
Contract liabilities	$ 0		$ 0		$ 0
Number of real estate assets sold during the period \| Asset	0	0	0	0
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	$ 6,831	$ 6,892	$ 19,343	$ 19,994
Bank owned life insurance	301	237	813	713
Other	1,028	657	2,773	1,989
Total	2,492	2,134	6,862	6,294
Service Charges on Deposit Accounts
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	2,883	3,166	8,323	9,166
Overdraft Fees [Member] \| Retail [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	1,970	2,161	5,582	6,177
Overdraft Fees [Member] \| Business [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	361	408	1,123	1,153
Account Service Charges [Member] \| Retail [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	552	519	1,609	1,607
Account Service Charges [Member] \| Business [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	0	78	9	229
Other Deposit Related Income [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	713	727	2,079	2,158
ATM Fees [Member] \| Retail [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	373	374	1,041	1,077
ATM Fees [Member] \| Business [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	9	10	26	26
Other [Member] \| Retail [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	240	219	703	656
Other [Member] \| Business [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	91	124	309	399
Interchange Income [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	2,785	2,486	7,744	7,236
Investment and Insurance Commissions [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	450	513	1,197	1,434
Asset Management Revenue [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	292	274	823	826
Transaction Based Revenue [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	$ 158	$ 239	$ 374	$ 608