Income Taxes - Carry Amounts of the Low Income Housing Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Income Taxes
Low income housing investments	$ 3,998	$ 4,304

Represents the amount of estimated gain or loss recognized during the period from investments in low income housing partnerships.

No definition available.

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