Income classified as other excluding interest income.

No definition available.

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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

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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

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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
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-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

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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://fasb.org/us-gaap/role/ref/legacyRef
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+ 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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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

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

- References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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- 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.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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Data Type:	na
Balance Type:
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- Details

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Data Type:	na
Balance Type:
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- Details

Name:	srt_MajorCustomersAxis=ibcp_CustomerRetailMember
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Name:	srt_MajorCustomersAxis=ibcp_CustomerBusinessMember
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Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
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Data Type:	na
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Revenue from Contracts with Customers (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) Asset	Jun. 30, 2017 USD ($)
Revenue from Contracts with Customers [Abstract]
Percentage of revenues excluded from ASU 2014-09	82.80%	79.70%	82.80%	79.70%
Number of realestate assets sold during the period \| Asset			0
Contract assets	$ 0		$ 0
Contract liabilities	0		0
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	6,824		13,102
Bank owned life insurance	220		476
Other	772		1,332
Total	2,217	$ 2,114	4,160	$ 4,099
Service Charges on Deposits [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	3,095		6,000
Overdraft Fees [Member] \| Retail [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	2,044		4,016
Overdraft Fees [Member] \| Business [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	380		745
Account Service Charges [Member] \| Retail [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	588		1,088
Account Service Charges [Member] \| Business [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	83		151
Other Deposit Related Income [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	742		1,431
ATM Fees [Member] \| Retail [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	358		703
ATM Fees [Member] \| Business [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	8		16
Other [Member] \| Retail [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	230		437
Other [Member] \| Business [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	146		275
Interchange Income [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	2,504		4,750
Investment and Insurance Commissions [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	483		921
Asset Management Revenue [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	281		552
Transaction Based Revenue [Member]
Disaggregation of Revenue Sources by Attributes [Abstract]
Revenue from contracts with customers	$ 202		$ 369