Accelerated cash payment.

No definition available.

Name:	bbsi_AcceleratedCashPayment
Namespace Prefix:	bbsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Accelerated cash payment remaining amount.

+ References

No definition available.

+ Details

Name:	bbsi_AcceleratedCashPaymentRemainingAmount
Namespace Prefix:	bbsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt Instrument Covenant Maximum Capital Expenditure Threshold Year One

+ References

No definition available.

+ Details

Name:	bbsi_DebtInstrumentCovenantMaximumCapitalExpenditureThresholdYearOne
Namespace Prefix:	bbsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt Instrument Covenant Maximum Capital Expenditure Threshold Year Two

+ References

No definition available.

+ Details

Name:	bbsi_DebtInstrumentCovenantMaximumCapitalExpenditureThresholdYearTwo
Namespace Prefix:	bbsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fixed charge coverage ratios.

+ References

No definition available.

+ Details

Name:	bbsi_FixedChargeCoverageRatios
Namespace Prefix:	bbsi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Prohibition for purchase money financing on incurring additional indebtedness without the prior approval of the bank.

+ References

No definition available.

+ Details

Name:	bbsi_ProhibitionForPurchaseMoneyFinancingOnIncurringAdditionalIndebtednessWithoutPriorApprovalOfBank
Namespace Prefix:	bbsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Ratio of restricted and unrestricted cash and marketable securities to workers compensation and safety incentive liabilities measured quarterly basis.

+ References

No definition available.

+ Details

Name:	bbsi_RestrictedAndUnrestrictedCashAndMarketableSecuritiesToWorkersCompensationAndSafetyIncentiveLiabilitiesRatio
Namespace Prefix:	bbsi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Restricted money market funds and certificates of deposit current.

+ References

No definition available.

+ Details

Name:	bbsi_RestrictedMoneyMarketFundsAndCertificatesOfDepositCurrent
Namespace Prefix:	bbsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 9

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Conversion Rate
-URI http://asc.fasb.org/extlink&oid=6509012

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(5))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateTerms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

+ Details

Name:	us-gaap_DividendsPayableAmountPerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Description of the fees for amounts available, but unused under the credit facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeeDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the required periodic payment applied to principal.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

+ Details

Name:	us-gaap_SecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=bbsi_CreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=bbsi_CurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=bbsi_WellFargoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=bbsi_LiborFloatingInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=bbsi_LiborFixedInterestRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=bbsi_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_StandbyLettersOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=bbsi_UnsecuredLettersOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Revolving Credit Facility and Long-Term Debt - Additional Information (Detail)					3 Months Ended		12 Months Ended
	Dec. 31, 2016 USD ($)	May. 24, 2016 USD ($)	Jun. 30, 2015	Dec. 31, 2014 USD ($)	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2015 USD ($) $ / shares
Line of Credit Facility [Line Items]
Restricted money market funds and restricted certificates of deposit, current							$ 92,400,000
Scenario Forecast [Member]
Line of Credit Facility [Line Items]
Accelerated cash payment	$ 5,000,000
Subsequent Event [Member]
Line of Credit Facility [Line Items]
Accelerated cash payment		$ 2,500,000
Agreement [Member]
Line of Credit Facility [Line Items]
Restricted money market funds and restricted certificates of deposit, current							$ 92,400,000
Line of credit facility commitment fee description							The Agreement also provides for an unused commitment fee of 0.35% per year on the average daily unused amount of the revolving credit facility, and a fee of 1.75% of the face amount of each letter of credit
Minimum fixed charge coverage ratio							150.00%
Maximum amount of capital expenditures in 2015							$ 5,000,000
Maximum amount of capital expenditures in 2016							4,000,000
Funded debt to EBITDA ratio					1.75	1.75
Agreement [Member] \| Scenario Forecast [Member]
Line of Credit Facility [Line Items]
Accelerated cash payment	5,000,000
Accelerated cash payment, remaining amount	$ 2,500,000
Agreement [Member] \| Subsequent Event [Member]
Line of Credit Facility [Line Items]
Accelerated cash payment		$ 2,500,000
Agreement [Member] \| Current Assets [Member]
Line of Credit Facility [Line Items]
Restricted money market funds and restricted certificates of deposit, current							50,100,000
Wells Fargo [Member] \| Due On June 30, 2016 [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Term loan payment							5,000,000
Wells Fargo [Member] \| Due On September 30, 2016 [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Term loan payment							5,000,000
Wells Fargo [Member] \| Due On December 31, 2016 [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Term loan payment							$ 5,000,000
Minimum [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Minimum fixed charge coverage ratio					125.00%	125.00%	150.00%
Ratio of restricted and unrestricted cash and marketable securities to workers' compensation and safety incentive liabilities			100.00%	100.00%	100.00%	100.00%	100.00%
Prohibition on incurring additional indebtedness without the prior approval of the Bank in purchase money financing							$ 200,000
Maximum [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Prohibition on incurring additional indebtedness without the prior approval of the Bank in purchase money financing							$ 400,000
Cash dividend \| $ / shares							$ 0.22
Revolving Credit Facility [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Outstanding balance on term loan and revolving credit facility				$ 0			$ 0
Unused commitment fee on unused amount							0.35%
Credit facility, expiration date							Oct. 01, 2017
Revolving Credit Facility [Member] \| Wells Fargo [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity							$ 14,000,000
Revolving Credit Facility [Member] \| Daily Floating Rate [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description							A daily floating rate of one month LIBOR plus 2%
LIBOR plus rate							2.00%
Revolving Credit Facility [Member] \| Fixed Rate [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description							A fixed rate of LIBOR plus 2.0%
LIBOR plus rate							2.00%
Cash-Secured Letters of Credit [Member] \| Wells Fargo [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity							$ 88,300,000
Term Loan [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Outstanding balance on term loan and revolving credit facility				40,000,000			$ 15,000,000
Term loan from Bank, Interest rate description							One month LIBOR plus 2.25%
Term loan with principal bank				$ 5,100,000			$ 4,800,000
Payment of monthly principal installments of term loan							18,375
Term Loan [Member] \| Wells Fargo [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity							$ 40,000,000
Term loan maturity date							Dec. 31, 2016
Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
LIBOR plus rate							2.25%
Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Wells Fargo [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description							One month LIBOR plus 4.0%
LIBOR plus rate							4.00%
Standby Letters of Credit [Member] \| Wells Fargo [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity							$ 5,000,000
Unsecured Letters Of Credit [Member] \| Agreement [Member]
Line of Credit Facility [Line Items]
Unused commitment fee on unused amount							1.75%