Revenue Recognition - General Information (Details)	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2020
Revenue from Contract with Customer [Abstract]
Percentage of revenue outside of scope of ASC 606 (as a percent)	37.10%	29.60%

Noninterest Revenue Outside Scope of Accounting Standard Codification 606, Percentage

No definition available.

Name:	bsrr_NoninterestRevenueOutsideScopeOfAccountingStandardCodification606Percentage
Namespace Prefix:	bsrr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration