Repurchase Agreements - Summary of Repurchase Agreements Accounted as Secured Borrowings (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 90,885
Securities pledged for Repurchase Agreements, Total	121,593
Federal Agency Collateralized Mortgage Obligations [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements, Total	33,798
Federal Agency Mortgage-backed Pools [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements, Total	87,795
Remaining Contractual Maturity of the Agreements, Overnight and Continuous [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	90,885
Securities pledged for Repurchase Agreements, Total	121,593
Remaining Contractual Maturity of the Agreements, Overnight and Continuous [Member] \| Federal Agency Collateralized Mortgage Obligations [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements, Total	33,798
Remaining Contractual Maturity of the Agreements, Overnight and Continuous [Member] \| Federal Agency Mortgage-backed Pools [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities pledged for Repurchase Agreements, Total	$ 87,795

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

+ Details

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

- Definition

Carrying value, as of the balance sheet date, of securities sold under agreements to repurchase where the transferor maintains effective control over the assets, accounting for them as secured debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 10
-Section 55
-Paragraph 51
-URI http://asc.fasb.org/extlink&oid=109221364&loc=d3e101761-111710

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(m)(1)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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

- Definition

Amount, before effects of master netting arrangements, of securities loaned to entities in exchange for collateral. Includes liabilities not subject to a master netting arrangement and elected not to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

+ Details

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=hbnc_FederalAgencyCollateralizedMortgageObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AssetsSoldUnderAgreementsToRepurchaseMaturityPeriodsAxis=us-gaap_MaturityOvernightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: