Loans and Leases (Loans and leases not covered by share agreements (in text)) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable	$ 2,904,947	$ 2,825,170
Impaired loans, related allowance	7,141	4,624
Loans delinquent 30 to 89 days, percentage	0.69%
Nonpass
Financing Receivable, Recorded Investment [Line Items]
Percent of nonaccrual loans	18.00%	15.00%
Loans and leases receivable	259,183	279,847
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Percent of loans	50.00%	50.00%
Substandard
Financing Receivable, Recorded Investment [Line Items]
Percent of loans	45.00%	50.00%
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Percent of loans	5.00%
Performing Troubled Debt Restructured Loan
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable	13,000
Impaired loans, related allowance	$ 2,200

Financing Receivable, Recorded Investment, 30 to 89 Days Past Due, Percentage

No definition available.

Name:	htlf_FinancingReceivableRecordedInvestment30to89DaysPastDuePercentage
Namespace Prefix:	htlf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Financing Receivables, Recorded Investments, Nonaccrual Status, Percentage

+ References

No definition available.

+ Details

Name:	htlf_FinancingReceivablesRecordedInvestmentsNonaccrualStatusPercentage
Namespace Prefix:	htlf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Loans And Leases Receivable, Gross, Percentage

+ References

No definition available.

+ Details

Name:	htlf_LoansAndLeasesReceivableGrossPercentage
Namespace Prefix:	htlf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5212-111524

+ Details

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

- Definition

Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10(3))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Subparagraph 3

-Article 9

+ Details

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