Name:	htbk_AvailableForSaleSecuritiesAndHeldToMaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions
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Data Type:	xbrli:integerItemType
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Represents the holdings of securities as percentage of shareholders' equity, considered as threshold for disclosure purpose.

No definition available.

Name:	htbk_AvailableForSaleSecuritiesAsPercentageOfShareholdersEquityConsideredAsThresholdForDisclosurePurpose
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Data Type:	num:percentItemType
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Represents the number of investment positions in the available-for-sale investments as of the balance sheet date.

No definition available.

Name:	htbk_AvailableForSaleSecuritiesQualitativeDisclosureNumberOfPositions
Namespace Prefix:	htbk_
Data Type:	xbrli:integerItemType
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Represents the number of investment positions in the held to maturity investments as of the balance sheet date.

No definition available.

Name:	htbk_HeldToMaturitySecuritiesQualitativeDisclosureNumberOfPositions
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Data Type:	xbrli:integerItemType
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Represents the number of holdings of securities of any one issuer other than the U.S. Government and its sponsored entities, in the amount greater than 10% of shareholders' equity.

No definition available.

Name:	htbk_InvestmentSecuritiesQualitativeDisclosureNumberOfHoldingsOfSecuritiesOfAnyOneIssuerOtherThanUsGovernmentAndSponsoredEntities
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Data Type:	xbrli:integerItemType
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Represents the number of investment positions as of the balance sheet date.

No definition available.

Name:	htbk_InvestmentSecuritiesQualitativeDisclosureNumberOfPositions
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- References

No definition available.

Name:	us-gaap_DebtSecuritiesAvailableForSaleAndHeldToMaturityAbstract
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Data Type:	xbrli:stringItemType
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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for 12 months or longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27290-111563

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity), in continuous loss position for less than 12 months.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27290-111563

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
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Data Type:	xbrli:monetaryItemType
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Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for less than 12 months.

Name:	us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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Fair value of investment in debt security measured at amortized cost (held-to-maturity), in continuous unrealized loss position for 12 months or longer.