Loans - Aging of Past Due Loans by Class of Loans - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Aging of Past Due Loans by Class of Loans
Past due loans 30 day or greater	$ 6,943	$ 7,989
Nonaccrual loans - held-for-investment	2,250	3,059
30 days or greater past due
Aging of Past Due Loans by Class of Loans
30 days or greater past due nonaccrual loans	1,410	2,057
Less than 30 days past due
Aging of Past Due Loans by Class of Loans
Less than 30 days past due nonaccrual loans held-for-investment	$ 840	$ 1,002

Represents the recorded investment in financing receivables held for investment, which are less than 30 days past due and on nonaccrual status as of the balance sheet date.

No definition available.

+ Details

Name:	htbk_FinancingReceivableRecordedInvestmentLessThan30DaysPastDueNonaccrualStatus
Namespace Prefix:	htbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Recorded investment in financing receivables 30 days or greater past due that are on nonaccrual status as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	htbk_FinancingReceivableRecordedInvestmentNonaccrualStatus30DaysOrGreaterPastDue
Namespace Prefix:	htbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

+ Details

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

- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=htbk_FinancingReceivablesEqualToGreaterThan30DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables1To29DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: