Gain (Loss) On Sale Of Mortgage Servicing Rights

No definition available.

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

- Definition

Mortgage Loans Serviced for Others, Amount

+ References

No definition available.

+ Details

Name:	htlf_MortgageLoansServicedForOthersAmount
Namespace Prefix:	htlf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Servicing Asset, Agreement Term

+ References

No definition available.

+ Details

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

- Definition

Servicing Asset At Amortized Cost, Amortization, Term

+ References

No definition available.

+ Details

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

- Definition

Servicing Asset At Fair Value, Unpaid Principal Balance

+ References

No definition available.

+ Details

Name:	htlf_ServicingAssetAtFairValueUnpaidPrincipalBalance
Namespace Prefix:	htlf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Valuation servicing rights in tranches [Line Items]

+ References

No definition available.

+ Details

Name:	htlf_ValuationServicingRightsInTranchesLineItems
Namespace Prefix:	htlf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

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

- Definition

Income from mortgage banking activities (fees and commissions) and servicing real estate mortgages, credit cards, and other financial assets held by others net of any related impairment of capitalized service costs. Also includes any premiums received in lieu of regular servicing fees on such loans only as earned over the life of the loans.

+ References

No definition available.

+ Details

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

- Definition

The net cash outflow or inflow associated with acquisition or sale of mortgage servicing rights which is the net carrying value of capitalized servicing rights, which contractually entitle the servicer to receive fees and ancillary revenues for performing billing, collection, disbursement and recordkeeping services in connection with a mortgage portfolio. Rights may be obtained via (1) acquisition or assumption of a servicing obligation that does not relate to financial assets of the servicer or its consolidated affiliates; or (2) by originating mortgage loans and then (a) transferring the loans to a Variable Interest Entity (VIE) in a transaction that meets the necessary transfer and classification requirements, or (b) transferring the loans in a transaction that meets the requirements for sale accounting.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24072-122690

+ Details

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

- Definition

Aggregate amount of servicing assets that are subsequently measured at fair value and servicing assets that are subsequently measured using the amortization method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

+ Details

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

- Definition

Fair value of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=7516967&loc=d3e66267-113978

+ Details

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

- Definition

Amount of increase (decrease) in the amortized amount from a decrease (increase) in the valuation allowance applied to the servicing asset for a contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

+ Details

Name:	us-gaap_ServicingAssetAtAmortizedValueValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Decrease in servicing assets subsequently measured at fair value resulting from conveyance of servicing rights to unrelated parties.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122625-111746

+ Details

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

- Definition

Value of input used to measure servicing asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

Name:	us-gaap_ServicingAssetMeasurementInput
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Discount rate used to estimate the fair value of servicing assets and servicing liabilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122596-111746

+ Details

Name:	us-gaap_ServicingAssetsAndServicingLiabilitiesAtFairValueAssumptionsUsedToEstimateFairValueDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Estimated rate of prepayments of principal on servicing assets and servicing liabilities.

+ References

+ Details

Name:	us-gaap_ServicingAssetsAndServicingLiabilitiesAtFairValueAssumptionsUsedToEstimateFairValuePrepaymentSpeed
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=htlf_PNCBankN.A.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=htlf_MortgageServicingRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputCapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=htlf_DubuqueBankAndTrustCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=htlf_FirstBankTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=htlf_CommercialServicingRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=htlf_CommercialServicingRightslessthan20YearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=htlf_CommercialServicingRightsmorethan20YearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=htlf_MortgageServicingRights15YearTrancheMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=htlf_MortgageServicingRights30YearTrancheMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

GOODWILL, CORE DEPOSIT INTANGIBLES AND OTHER INTANGIBLE ASSETS (Mortgage and Commercial Loans Servicing Narrative) (Details)		12 Months Ended
	Apr. 30, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Aug. 01, 2019 USD ($)
Valuation servicing rights in tranches [Line Items]
Mortgage loans serviced for others		$ 743,300,000	$ 616,700,000
Custodial escrow balances maintained		5,700,000	5,000,000.0
Servicing rights, net		6,052,000	6,736,000
PNC Bank, N.A.
Valuation servicing rights in tranches [Line Items]
Custodial escrow balances maintained					$ 22,900,000
Mortgage Servicing Rights
Valuation servicing rights in tranches [Line Items]
Fair value of mortgage servicing rights		$ 5,189,000	5,621,000
Discount rate		9.03%
Fees collected for servicing of mortgage loans		$ 1,700,000	$ 4,900,000	$ 9,900,000
Mortgage Servicing Rights \| Minimum
Valuation servicing rights in tranches [Line Items]
Prepayment rate (as a percent)		16.20%
Discount rate		9.02%	9.02%
Mortgage Servicing Rights \| Minimum \| Measurement Input, Cap Rate
Valuation servicing rights in tranches [Line Items]
Average capitalization rate (percent)		0.0076	0.0080
Mortgage Servicing Rights \| Maximum \| Measurement Input, Cap Rate
Valuation servicing rights in tranches [Line Items]
Average capitalization rate (percent)		0.0116	0.0103
Mortgage Servicing Rights \| Dubuque Bank and Trust Company
Valuation servicing rights in tranches [Line Items]
Unpaid principal balance	$ 3,310,000,000
Mortgage servicing rights			$ 20,600,000
Cash received from sale of Mortgage servicing rights			36,600,000
Gain on sale of mortgage servicing rights			$ 14,500,000
Mortgage Servicing Rights \| First Bank & Trust
Valuation servicing rights in tranches [Line Items]
Prepayment rate (as a percent)			14.20%
Commercial Servicing Rights
Valuation servicing rights in tranches [Line Items]
Fair value of mortgage servicing rights		$ 1,288,000	$ 1,594,000
Fees collected for servicing of mortgage loans		879,000	1,000,000.0
Servicing rights, net		$ 66,200,000	$ 82,100,000
Commercial Servicing Rights \| Minimum
Valuation servicing rights in tranches [Line Items]
Prepayment rate (as a percent)		14.95%	14.25%
Discount rate		7.70%	10.65%
Commercial Servicing Rights \| Minimum \| Measurement Input, Cap Rate
Valuation servicing rights in tranches [Line Items]
Average capitalization rate (percent)		0.0310	0.0310
Commercial Servicing Rights \| Maximum
Valuation servicing rights in tranches [Line Items]
Prepayment rate (as a percent)		19.25%	18.08%
Discount rate		12.88%	13.94%
Commercial Servicing Rights \| Maximum \| Measurement Input, Cap Rate
Valuation servicing rights in tranches [Line Items]
Average capitalization rate (percent)		0.0445	0.0445
Commercial Servicing Rights less than 20 Years
Valuation servicing rights in tranches [Line Items]
Fair value of mortgage servicing rights		$ 203,000	$ 285,000
Servicing rights, term		20 years
Servicing rights, valuation allowance		$ 0	0
Amortization period		20 years
Commercial Servicing Rights more than 20 Years
Valuation servicing rights in tranches [Line Items]
Fair value of mortgage servicing rights		$ 1,085,000	1,309,000
Servicing rights, term		20 years
Servicing rights, valuation allowance		$ 0	$ 0
Amortization period			20 years
Mortgage Servicing Rights 15-year Tranche
Valuation servicing rights in tranches [Line Items]
Fair value of mortgage servicing rights		1,100,000	$ 1,368,000
Servicing rights, valuation allowance		$ 422,000	$ 114,000
Amortization period		15 years	15 years
Mortgage Servicing Rights 30-year Tranche
Valuation servicing rights in tranches [Line Items]
Fair value of mortgage servicing rights		$ 4,089,000	$ 4,253,000
Servicing rights, valuation allowance		$ 1,356,000	$ 797,000
Amortization period		30 years	30 years