Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2020	Aug. 01, 2020
Cover [Abstract]
Entity Central Index Key	0001130144
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity File Number	000-33063
Entity Registrant Name	SIERRA BANCORP
Entity Incorporation, State or Country Code	CA
Entity Tax Identification Number	33-0937517
Entity Address, Address Line One	86 North Main Street
Entity Address, City or Town	Porterville
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	93257
City Area Code	559
Local Phone Number	782-4900
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
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	BSRR
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		15,192,838
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Amendment Flag	false