XML 52 R37.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Fair Value Measurement - Summary of Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | $ 392,615 | $ 304,690
Gross Unrealized Gains (Losses) | (1,936) | (5)
Recorded Basis | 390,679 | 304,685
Investments Current [Member] | Cash and Cash Equivalents [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 221 | 1,943
Recorded Basis | 221 | 1,943
Investments Current [Member] | Cash and Cash Equivalents [Member] | Money Market Funds [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 121 | 1,943
Recorded Basis | 121 | 1,943
Investments Current [Member] | Cash and Cash Equivalents [Member] | U.S. Treasuries [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 100 |
Recorded Basis | 100 |
Investments Current [Member] | Investments [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 674 | 5,675
Recorded Basis | 674 | 5,675
Investments Current [Member] | Investments [Member] | U.S. Treasuries [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 199 |
Recorded Basis | 199 |
Investments Current [Member] | Investments [Member] | Corporate Bonds [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 400 | 225
Gross Unrealized Gains (Losses) |  | (1)
Recorded Basis | 400 | 224
Investments Current [Member] | Investments [Member] | U.S. Government Agency Securities [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 65 |
Recorded Basis | 65 |
Investments Current [Member] | Investments [Member] | Municipal Bonds [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 10 | 713
Gross Unrealized Gains (Losses) |  | 1
Recorded Basis | 10 | 714
Investments Current [Member] | Investments [Member] | Certificates of Deposit [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost |  | 4,737
Recorded Basis |  | 4,737
Investments Noncurrent [Member] | Investments [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 1,208 | 643
Gross Unrealized Gains (Losses) | (9) | (1)
Recorded Basis | 1,199 | 642
Investments Noncurrent [Member] | Investments [Member] | U.S. Treasuries [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 202 |
Gross Unrealized Gains (Losses) | (2) |
Recorded Basis | 200 |
Investments Noncurrent [Member] | Investments [Member] | Corporate Bonds [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 419 | 567
Gross Unrealized Gains (Losses) | (2) | (1)
Recorded Basis | 417 | 566
Investments Noncurrent [Member] | Investments [Member] | Municipal Bonds [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost |  | 76
Recorded Basis |  | 76
Investments Noncurrent [Member] | Investments [Member] | Mortgage Backed Securities [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 577 |
Gross Unrealized Gains (Losses) | (5) |
Recorded Basis | 572 |
Investments Noncurrent [Member] | Investments [Member] | Asset Backed Securities [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 10 |
Recorded Basis | 10 |
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 390,512 | 296,429
Gross Unrealized Gains (Losses) | (1,927) | (4)
Recorded Basis | 388,585 | 296,425
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Money Market Funds [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 16,018 | 284,593
Recorded Basis | 16,018 | 284,593
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | U.S. Treasuries [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 45,833 | 834
Gross Unrealized Gains (Losses) | (143) |
Recorded Basis | 45,690 | 834
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Corporate Bonds [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 184,808 | 2,886
Gross Unrealized Gains (Losses) | (953) | 2
Recorded Basis | 183,855 | 2,888
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | U.S. Government Agency Securities [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 38,168 |
Gross Unrealized Gains (Losses) | (222) |
Recorded Basis | 37,946 |
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Municipal Bonds [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 472 | 2,069
Gross Unrealized Gains (Losses) | (14) | (6)
Recorded Basis | 458 | 2,063
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Certificates of Deposit [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost |  | 6,047
Recorded Basis |  | $ 6,047
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Mortgage Backed Securities [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 86,240 |
Gross Unrealized Gains (Losses) | (595) |
Recorded Basis | 85,645 |
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Commercial Paper [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |
Cost | 18,973 |
Recorded Basis | $ 18,973 |

X
- Definition This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before tax of unrealized gain (loss) in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, and (3) securities available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.4) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_MarketableSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=bbsi_MarketableSecuritiesCurrentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_InvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CorporateBondSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_MunicipalBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=bbsi_MarketableSecuritiesNoncurrentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=bbsi_RestrictedCashAndInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CommercialPaperMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |