Severance and retention acquisition costs incurred during the period.

No definition available.

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Namespace Prefix:	htbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=116868678&loc=d3e1043-128460

+ Details

Name:	us-gaap_BusinessCombinationAcquisitionRelatedCosts
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- Definition

Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessCombinationIntegrationRelatedCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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- Details

Name:	us-gaap_BusinessAcquisitionAxis=htbk_PresidioBankMember
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Period Type:

Business combinations - Pre-tax merger-related costs (Details) - USD ($)	3 Months Ended							12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Salaries and employee benefits								$ 356,000	$ 6,580,000	$ 3,569,000
Other								2,245,000	4,500,000	5,598,000
Total merger-related costs	$ 101,000	$ 17,000	$ 59,000	$ 2,424,000	$ 9,879,000	$ 661,000	$ 540,000	2,601,000	11,080,000	9,167,000
Presidio bank
Business Acquisition [Line Items]
Salaries and employee benefits								356,000	6,580,000	3,569,000
Other								2,245,000	4,500,000	5,598,000
Total merger-related costs								$ 2,601,000	$ 11,080,000	$ 9,167,000