Benefit Plans - Deferred Compensation Plan (Details)	12 Months Ended
Dec. 31, 2017
Deferred Compensation Plan
Maximum percentage of board fees deferred by participating director into deferred account	100.00%
Maximum term of distribution schedule elected by director	10 years

Represents the maximum percentage of board fees deferred by participating director into deferred account.

No definition available.

Name:	htbk_DeferredCompensationArrangementMaximumPercentageOfBoardFeesDeferredByParticipatingDirectorIntoDeferredAccount
Namespace Prefix:	htbk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration