Remaining unamortized intangible assets relating to customers and deposits associated with the pending Branch Sale.

No definition available.

Name:	ibcp_AmountOfRemainingUnamortizedIntangibleAssets
Namespace Prefix:	ibcp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	ibcp_BranchLocationLineItems
Namespace Prefix:	ibcp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Cost, net of depreciation, of fixed assets expected to be sold and classified as held for sale.

+ References

No definition available.

+ Details

Name:	ibcp_CostNetOfDepreciationOfFixedAssetsExpectedToBeSold
Namespace Prefix:	ibcp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of the payment of deposit premium on core deposits.

+ References

No definition available.

+ Details

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

- Definition

Gross amount of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others, net of adjustments.

+ References

No definition available.

+ Details

Name:	ibcp_DepositsGross
Namespace Prefix:	ibcp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Refers to the percentage of discount of branches being sold.

+ References

No definition available.

+ Details

Name:	ibcp_DiscountPercentageOfBranchesBeingSold
Namespace Prefix:	ibcp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Existing core deposit intangibles allocation related to branch sale.

+ References

No definition available.

+ Details

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

- Definition

Refers to the fair value of fixed assets expected to be sold and are classified as held for sale.

+ References

No definition available.

+ Details

Name:	ibcp_FairValueOfFixedAssetsExpectedToBeSold
Namespace Prefix:	ibcp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Gain (loss) from sale of branches.

+ References

No definition available.

+ Details

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

- Definition

Gain (loss) on sale of fixed assets allocation related to Branch sale.

+ References

No definition available.

+ Details

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

- Definition

Loss on the sale of loans allocation related to Branch sale.

+ References

No definition available.

+ Details

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

- Definition

Refers to the number of branches to be sold.

+ References

No definition available.

+ Details

Name:	ibcp_NumberOfBranchesToBeSold
Namespace Prefix:	ibcp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Transaction related costs allocation related to Branch sale.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_StatementGeographicalAxis=ibcp_BattleCreekMichiganMarketAreaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=ibcp_MidlandMichiganMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=ibcp_NortheastMichiganMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

BRANCH SALE (Details) (USD $)	12 Months Ended
BRANCH SALE (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Branch Location [Line Items]
Deposit premium payment			$ 11,500,000
Fair value of fixed assets expected to be sold			48,000,000
Discount percentage of branches being sold (in hundredths)			1.75%
Cost of fixed assets expected to be sold, net of accumulated depreciation			8,100,000
Amount of remaining unamortized intangible assets			336,100,000
Net gain on branch sale	0ibcp_GainOnBranchSale	0ibcp_GainOnBranchSale	5,402,000ibcp_GainOnBranchSale
Existing core deposit intangibles allocation related to Branch sale			2,600,000
Loss on sale of fixed assets allocation related to Branch sale			2,500,000
Loss on the sale of loans allocation related to Branch sale			200,000
Transaction related costs allocation related to Branch sale			800,000
Midland, Michigan [Member]
Branch Location [Line Items]
Number of branches to be sold			21
Deposits			$ 403,100,000
Battle Creek, Michigan market area [Member]
Branch Location [Line Items]
Number of branches to be sold			6
Northeast Michigan [Member]
Branch Location [Line Items]
Number of branches to be sold			15