Nature of Operations and Basis of Presentation (Details)	12 Months Ended
Dec. 31, 2020 segment item
Nature of Operations and Basis of Presentation
Number of branches	30
Number of reportable segments \| segment	1
San Francisco and Los Angeles, California
Nature of Operations and Basis of Presentation
Number of branches	26

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8672-108599

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration