Loans and Allowance for Credit Losses on Loans - Troubled Debt Restructurings (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Loans and Allowance for Credit Losses on Loans
Recorded investment of troubled debt restructurings	$ 1,000	$ 500,000
Troubled debt restructurings, nonaccrual loans		372,000
Troubled debt restructurings, accruing loans		128,000
Specific reserves	0	290,000
Additional loan committed on any loans classified as troubled debt restructuring.	$ 0	$ 0

Additional loan committed on any loans classified as troubled debt restructuring.

No definition available.

Name:	htbk_AdditionalLoanCommittedOnLoansClassifiedAsTroubledDebtRestructuring
Namespace Prefix:	htbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Allowance for credit losses with specific reserves.

+ References

No definition available.

+ Details

Name:	htbk_AllowanceForCreditLossesWithSpecificReserves
Namespace Prefix:	htbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings and are on nonaccrual status as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	htbk_FinancingReceivableModificationsRecordedInvestmentNonaccrualStatus
Namespace Prefix:	htbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings and are still accruing as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	htbk_FinancingReceivableModificationsRecordedInvestmentStillAccruing
Namespace Prefix:	htbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of financing receivable modified as troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=121585226&loc=d3e18845-111554

+ Details

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