    <SEC-DOCUMENT>0000950170-24-046428-index.html : 20240422
    <SEC-HEADER>0000950170-24-046428.hdr.sgml : 20240422
    <ACCEPTANCE-DATETIME>20240422161512
    ACCESSION NUMBER:		0000950170-24-046428
    CONFORMED SUBMISSION TYPE:	DEF 14A
    PUBLIC DOCUMENT COUNT:		15
    CONFORMED PERIOD OF REPORT:	20240422
    FILED AS OF DATE:		20240422
    DATE AS OF CHANGE:		20240422

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			BARRETT BUSINESS SERVICES INC
    		CENTRAL INDEX KEY:			0000902791
    		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-HELP SUPPLY SERVICES [7363]
    		ORGANIZATION NAME:           	07 Trade & Services
    		IRS NUMBER:				520812977
    		STATE OF INCORPORATION:			MD
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		DEF 14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-21886
    		FILM NUMBER:		24861356

    	BUSINESS ADDRESS:
    		STREET 1:		8100 NE PARKWAY DRIVE
    		STREET 2:		SUITE 200
    		CITY:			VANCOUVER
    		STATE:			WA
    		ZIP:			98662
    		BUSINESS PHONE:		(800) 494-5669

    	MAIL ADDRESS:
    		STREET 1:		8100 NE PARKWAY DRIVE
    		STREET 2:		SUITE 200
    		CITY:			VANCOUVER
    		STATE:			WA
    		ZIP:			98662
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>DEF 14A
    <SEQUENCE>1
    <FILENAME>bbsi-20240422.htm
    <DESCRIPTION>DEF 14A
    <TEXT>
    Document 1 - file: bbsi-20240422.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>img41456027_0.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 2 - file: img41456027_0.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>img41456027_1.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: img41456027_1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>img41456027_2.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: img41456027_2.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>img41456027_3.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: img41456027_3.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>6
    <FILENAME>bbsi-20240422.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA WITH EMBEDDED LINKBASES DOCUMENT
    <TEXT>
    Document 6 - file: bbsi-20240422.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>8
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 8 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>9
    <FILENAME>R2.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 9 - file: R2.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>10
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 10 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>11
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 11 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>13
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 13 - file: FilingSummary.html

    Document 13 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>15
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 15 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>16
    <FILENAME>0000950170-24-046428-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 16 - file: 0000950170-24-046428-xbrl.zip

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>18
    <FILENAME>bbsi-20240422_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 18 - file: bbsi-20240422_htm.html

    Document 18 - RAW XML: bbsi-20240422_htm.xml

    </DOCUMENT>
    </SEC-DOCUMENT>