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v3.20.4

Summary of Significant Accounting Policies - Premises and Equipment (Details) | 12 Months Ended
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Dec. 31, 2020 building
Premises and Equipment |
Number of buildings owned | 1
Building |
Premises and Equipment |
Estimated useful life | 40 years
Furniture | Minimum |
Premises and Equipment |
Estimated useful life | 5 days
Furniture | Maximum |
Premises and Equipment |
Estimated useful life | 15 years
Equipment | Minimum |
Premises and Equipment |
Estimated useful life | 5 years
Equipment | Maximum |
Premises and Equipment |
Estimated useful life | 15 years
Leasehold improvements | Minimum |
Premises and Equipment |
Estimated useful life | 5 years
Leasehold improvements | Maximum |
Premises and Equipment |
Estimated useful life | 15 years

X
- Definition Represents the number of buildings owned by the entity. + References No definition available. + Details
Name: | htbk_NumberOfBuildingsOwned
Namespace Prefix: | htbk_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentNetByTypeAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FurnitureAndFixturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_EquipmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_LeaseholdImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |