Loans Acquired and Other Real Estate Owned, Number of Loss Share Agreements

No definition available.

Name:	htlf_LoansAcquiredAndOtherRealEstateOwnedNumberOfLossShareAgreements
Namespace Prefix:	htlf_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans Acquired and Other Real Estate Owned, Recovery and Loss Sharing Agreement Term

+ References

No definition available.

+ Details

Name:	htlf_LoansAcquiredAndOtherRealEstateOwnedRecoveryAndLossSharingAgreementTerm
Namespace Prefix:	htlf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans Acquired and Other Real Estate Owned, Shared Loss Arrangement, Maximum Covered Assets

+ References

No definition available.

+ Details

Name:	htlf_LoansAcquiredAndOtherRealEstateOwnedSharedLossArrangementMaximumCoveredAssets
Namespace Prefix:	htlf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 15

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

+ Details

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

- Definition

Amount of contractually required payments receivable at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

+ Details

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

- Definition

Reserve for loans impairments recorded after acquisition as a result of current information and events which result in it being probable that estimated cash flows will be less than previously expected or because actual cash flows are less than cash flows previously expected. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 15

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)(2)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

+ Details

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

- Details

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

- Details

Name:	dei_LegalEntityAxis=htlf_GalenaStateBankTrustCoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=htlf_ElizabethStateBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loans and Leases (Troubled Debt in Text) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014 agreements	Jul. 02, 2009	Dec. 31, 2013
Galena State Bank & Trust Co.
Financing Receivable, Modifications [Line Items]
Number of loss share agreements	2
Shared loss arrangement, maximum covered assets	$ 10,000,000
Galena State Bank & Trust Co. \| Residential Real Estate
Financing Receivable, Modifications [Line Items]
Loss sharing agreement, term	10 years
Galena State Bank & Trust Co. \| Losses \| Non-residential Real Estate
Financing Receivable, Modifications [Line Items]
Loss sharing agreement, term	5 years
Galena State Bank & Trust Co. \| Recoveries \| Non-residential Real Estate
Financing Receivable, Modifications [Line Items]
Loss sharing agreement, term	8 years
Elizabeth State Bank
Financing Receivable, Modifications [Line Items]
Contractually required payments of loans acquired		42,700,000
Estimated fair value of loans acquired		37,800,000
Elizabeth State Bank \| Impaired Purchased Loans
Financing Receivable, Modifications [Line Items]
Contractually required payments of loans acquired		13,800,000
Estimated fair value of loans acquired		9,000,000
Allowance for loan and lease losses related to ASC 310-30 loans	0		0
Elizabeth State Bank \| Nonimpaired Purchased Loans
Financing Receivable, Modifications [Line Items]
Contractually required payments of loans acquired		28,900,000
Estimated fair value of loans acquired		$ 28,700,000