Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 30, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	000-23877
Entity Registrant Name	HERITAGE COMMERCE CORP
Entity Incorporation, State or Country Code	CA
Entity Tax Identification Number	77-0469558
Entity Address, Address Line One	224 Airport Parkway
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95110
City Area Code	408
Local Phone Number	947-6900
Title of 12(b) Security	Common Stock, No Par Value
Trading Symbol	HTBK
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		60,206,566
Document Fiscal Year Focus	2021
Entity Central Index Key	0001053352
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Amendment Flag	false