Barrett Business Services (BBSI) 10-Q 4 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 21, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Trading Symbol	BBSI
Entity Registrant Name	BARRETT BUSINESS SERVICES INC
Entity Central Index Key	0000902791
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		7,558,205
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, Par Value $0.01 Per Share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	MD
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	0-21886
Entity Tax Identification Number	52-0812977
Entity Address, Address Line One	8100 NE Parkway Drive
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Vancouver
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98662
City Area Code	360
Local Phone Number	828-0700

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 2,469	$ 68,688
Investments	107,284	101,244
Trade accounts receivable, net	226,582	118,506
Income taxes receivable	3,005	6,485
Prepaid expenses and other	18,437	15,961
Restricted cash and investments	104,640	96,991
Total current assets	462,417	407,875
Property, equipment and software, net	35,515	34,916
Operating lease right-of-use assets	23,208	23,025
Restricted cash and investments	294,364	258,153
Goodwill	47,820	47,820
Other assets	2,794	3,161
Total assets	866,118	774,950
Current liabilities:
Current portion of long-term debt	221	221
Accounts payable	4,606	4,746
Accrued payroll, payroll taxes and related benefits	235,928	149,989
Current operating lease liabilities	7,748	7,539
Other accrued liabilities	65,415	7,275
Workers' compensation claims liabilities	86,047	102,040
Safety incentives liability	6,883	18,827
Total current liabilities	406,848	290,637
Long-term workers' compensation claims liabilities	229,686	255,706
Long-term debt	3,399	3,510
Deferred income taxes	3,328	4,518
Long-term operating lease liabilities	16,525	16,419
Customer deposits and other long-term liabilities	6,910	5,925
Total liabilities	666,696	576,715
Commitments and contingencies (Notes 4 and 6)
Stockholders' equity:
Common stock, $.01 par value; 20,500 shares authorized, 7,523 and 7,566 shares issued and outstanding	75	76
Additional paid-in capital	27,437	24,885
Accumulated other comprehensive income	4,465	7,564
Retained earnings	167,445	165,710
Total stockholders' equity	199,422	198,235
Total liabilities and stockholders' equity	$ 866,118	$ 774,950

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	20,500,000	20,500,000
Common stock, shares issued	7,523,000	7,566,000
Common stock, shares outstanding	7,523,000	7,566,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Total revenues	$ 233,203	$ 201,031	$ 451,648	$ 420,135
Cost of revenues:
Total cost of revenues	175,730	154,388	363,310	347,441
Gross margin	57,473	46,643	88,338	72,694
Selling, general and administrative expenses	35,662	33,255	72,769	65,370
Depreciation and amortization	1,328	1,171	2,625	2,171
Income from operations	20,483	12,217	12,944	5,153
Other income (expense):
Investment income, net	1,965	1,800	3,734	4,767
Interest expense	(79)	(306)	(387)	(541)
Other, net	(13)	172	(4)	173
Other income, net	1,873	1,666	3,343	4,399
Income before income taxes	22,356	13,883	16,287	9,552
Provision for income taxes	5,266	2,373	3,751	1,449
Net income	$ 17,090	$ 11,510	$ 12,536	$ 8,103
Basic income per common share	$ 2.26	$ 1.52	$ 1.66	$ 1.07
Weighted average number of basic common shares outstanding	7,554	7,557	7,565	7,539
Diluted income per common share	$ 2.24	$ 1.51	$ 1.64	$ 1.06
Weighted average number of diluted common shares outstanding	7,645	7,647	7,658	7,678
Professional Employer Service Fees [Member]
Revenues:
Total revenues	$ 208,496	$ 180,488	$ 402,315	$ 374,080
Staffing Services [Member]
Revenues:
Total revenues	24,707	20,543	49,333	46,055
Direct Payroll Costs [Member]
Cost of revenues:
Total cost of revenues	18,498	15,796	36,948	34,873
Payroll Taxes and Benefits [Member]
Cost of revenues:
Total cost of revenues	111,719	93,671	234,502	213,133
Workers' Compensation [Member]
Cost of revenues:
Total cost of revenues	$ 45,513	$ 44,921	$ 91,860	$ 99,435

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 17,090	$ 11,510	$ 12,536	$ 8,103
Unrealized (losses) gains on investments, net of tax	2,151	6,877	(3,099)	4,142
Comprehensive income	$ 19,241	$ 18,387	$ 9,437	$ 12,245

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Unrealized (losses) gains on investments, tax	$ 828	$ 2,630	$ (1,179)	$ 1,584

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2019	$ 171,799	$ 75	$ 20,227	$ 2,819	$ 148,678
Beginning Balance, shares at Dec. 31, 2019		7,514
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	904	$ 1	903
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		56
Common stock repurchased on vesting of restricted stock units and performance awards	(378)		(378)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(6)
Share-based compensation expense	342		342
Company repurchase of common stock	(2,987)	$ (1)	(169)		(2,817)
Company repurchase of common stock, shares		(59)
Cash dividends on common stock	(2,262)				(2,262)
Unrealized gain (loss) on investments, net of tax	(2,735)			(2,735)
Net (loss) income	(3,407)				(3,407)
Ending Balance at Mar. 31, 2020	161,276	$ 75	20,925	84	140,192
Ending Balance, shares at Mar. 31, 2020		7,505
Beginning Balance at Dec. 31, 2019	171,799	$ 75	20,227	2,819	148,678
Beginning Balance, shares at Dec. 31, 2019		7,514
Unrealized gain (loss) on investments, net of tax	4,142
Net (loss) income	8,103
Ending Balance at Jun. 30, 2020	179,888	$ 76	23,421	6,961	149,430
Ending Balance, shares at Jun. 30, 2020		7,598
Beginning Balance at Mar. 31, 2020	161,276	$ 75	20,925	84	140,192
Beginning Balance, shares at Mar. 31, 2020		7,505
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	1,810	$ 1	1,809
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		96
Common stock repurchased on vesting of restricted stock units and performance awards	(110)		(110)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(3)
Share-based compensation expense	797		797
Cash dividends on common stock	(2,272)				(2,272)
Unrealized gain (loss) on investments, net of tax	6,877			6,877
Net (loss) income	11,510				11,510
Ending Balance at Jun. 30, 2020	179,888	$ 76	23,421	6,961	149,430
Ending Balance, shares at Jun. 30, 2020		7,598
Beginning Balance at Dec. 31, 2020	198,235	$ 76	24,885	7,564	165,710
Beginning Balance, shares at Dec. 31, 2020		7,566
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	815		815
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		38
Common stock repurchased on vesting of restricted stock units and performance awards	(107)		(107)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(1)
Share-based compensation expense	1,060		1,060
Company repurchase of common stock	(3,436)		(170)		(3,266)
Company repurchase of common stock, shares		(49)
Cash dividends on common stock	(2,278)				(2,278)
Unrealized gain (loss) on investments, net of tax	(5,250)			(5,250)
Net (loss) income	(4,554)				(4,554)
Ending Balance at Mar. 31, 2021	184,485	$ 76	26,483	2,314	155,612
Ending Balance, shares at Mar. 31, 2021		7,554
Beginning Balance at Dec. 31, 2020	198,235	$ 76	24,885	7,564	165,710
Beginning Balance, shares at Dec. 31, 2020		7,566
Unrealized gain (loss) on investments, net of tax	(3,099)
Net (loss) income	12,536
Ending Balance at Jun. 30, 2021	199,422	$ 75	27,437	4,465	167,445
Ending Balance, shares at Jun. 30, 2021		7,523
Beginning Balance at Mar. 31, 2021	184,485	$ 76	26,483	2,314	155,612
Beginning Balance, shares at Mar. 31, 2021		7,554
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	61		61
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		15
Common stock repurchased on vesting of restricted stock units and performance awards	(287)		(287)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(4)
Share-based compensation expense	1,335		1,335
Company repurchase of common stock	(3,142)	$ (1)	(155)		(2,986)
Company repurchase of common stock, shares		(42)
Cash dividends on common stock	(2,271)				(2,271)
Unrealized gain (loss) on investments, net of tax	2,151			2,151
Net (loss) income	17,090				17,090
Ending Balance at Jun. 30, 2021	$ 199,422	$ 75	$ 27,437	$ 4,465	$ 167,445
Ending Balance, shares at Jun. 30, 2021		7,523

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020
Statement Of Stockholders Equity [Abstract]
Cash dividends on common stock per share	$ 0.30	$ 0.30	$ 0.30	$ 0.30

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net income	$ 12,536	$ 8,103
Reconciliations of net income to net cash provided by (used in) operating activities:
Depreciation and amortization	2,625	2,171
Non-cash lease expense	3,937	3,545
Investment amortization and losses recognized	671	283
Deferred Income taxes		3,890
Share-based compensation	2,395	1,139
Changes in certain operating assets and liabilities:
Trade accounts receivable	(108,076)	(24,822)
Income taxes	3,480	(2,171)
Prepaid expenses and other	(2,476)	(2,458)
Accounts payable	(140)	(1,042)
Accrued payroll, payroll taxes and related benefits	87,024	8,035
Other accrued liabilities	58,051	(2,759)
Workers' compensation claims liabilities	(41,634)	(102,572)
Safety incentives liability	(11,944)	(2,183)
Operating lease liabilities	(3,805)	(3,405)
Other assets and liabilities, net	(23)	(143)
Net cash provided by (used in) operating activities	2,621	(114,389)
Cash flows from investing activities:
Purchase of property, equipment and software	(3,224)	(5,725)
Purchase of investments	(42,011)	(23,722)
Proceeds from sales and maturities of investments	40,054	38,547
Purchase of restricted investments	(253,048)	(29,570)
Proceeds from sales and maturities of restricted investments	46,690	22,453
Net cash (used in) provided by investing activities	(211,539)	1,983
Cash flows from financing activities:
Payments on long-term debt	(111)	(110)
Repurchase of common stock	(6,578)	(2,987)
Common stock repurchased on vesting of stock awards	(394)	(488)
Dividends paid	(4,549)	(4,534)
Proceeds from exercise of stock options	876	2,714
Net cash used in financing activities	(10,756)	(5,405)
Net decrease in cash, cash equivalents and restricted cash	(219,674)	(117,811)
Cash, cash equivalents and restricted cash, beginning of period	233,837	273,341
Cash, cash equivalents and restricted cash, end of period	$ 14,163	$ 155,530

Basis of Presentation of Interi

Basis of Presentation of Interim Period Statements	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation of Interim Period Statements	Note 1 - Basis of Presentation of Interim Period Statements The accompanying condensed consolidated financial statements are unaudited and have been prepared by Barrett Business Services, Inc. (“BBSI”, the “Company”, “our” or “we”), pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and note disclosures typically included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, the condensed consolidated financial statements include all adjustments, consisting only of normal recurring adjustments, necessary for a fair statement of the results for the interim periods presented. The accompanying condensed financial statements are prepared on a consolidated basis. All intercompany account balances and transactions have been eliminated in consolidation. The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results may differ from such estimates and assumptions. The condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s 2020 Annual Report on Form 10-K at pages 34 – 61. The results of operations for an interim period are not necessarily indicative of the results of operations for a full year. Revenue recognition Professional employer (“PEO”) services are normally used by organizations to satisfy ongoing needs related to the management of human capital and are governed by the terms of a client services agreement which covers all employees at a particular work site. Staffing revenues relate primarily to short-term staffing, contract staffing and on-site management services. The Company’s performance obligations for PEO and staffing services are satisfied, and the related revenue is recognized, as services are rendered by our workforce. Our PEO client service agreements have a minimum term of one year, are renewable on an annual basis, and typically require 30 days’ written notice to cancel or terminate the contract by either party. In addition, our client service agreements provide for immediate termination upon any default of the client regardless of when notice is given. PEO customers are invoiced following the end of each payroll processing cycle, with payment generally due on the invoice date. Staffing customers are generally invoiced weekly based on agreed rates per employee and actual hours worked, typically with payment terms of 30 days. The amount of earned but unbilled revenue is classified as a receivable on the condensed consolidated balance sheets. We report PEO revenues net of direct payroll costs because we are not the primary obligor for these payments to our clients’ employees. Direct payroll costs include salaries, wages, health insurance, and employee out-of-pocket expenses incurred incidental to employment. We also present revenue net of safety incentives because these incentives represent consideration payable to customers. Cost of revenues Our cost of revenues for PEO services includes employer payroll-related taxes and workers’ compensation costs. Our cost of revenues for staffing services includes direct payroll costs, employer payroll-related taxes, employee benefits, and workers’ compensation costs. Direct payroll costs represent the gross payroll earned by staffing services employees based on salary or hourly wages. Payroll taxes and employee benefits consist of the employer’s portion of Social Security and Medicare taxes, federal and state unemployment taxes, and staffing services employee reimbursements for materials, supplies and other expenses, which are paid by our customer. Workers’ compensation costs consist primarily of claims reserves, claims administration fees, legal fees, medical cost containment (“MCC”) expense, state administrative agency fees, third-party broker commissions, risk manager payroll, premiums for excess insurance, and the insured program, as well as costs associated with operating our two wholly owned insurance companies, Associated Insurance Company for Excess (“AICE”) and Ecole Insurance Company (“Ecole”). Cash and cash equivalents We consider non-restricted short-term investments that are highly liquid, readily convertible into cash, and have maturities at acquisition of less than three months, to be cash equivalents for purposes of the condensed consolidated statements of cash flows and condensed consolidated balance sheets. The Company maintains cash balances in bank accounts that normally exceed FDIC insured limits. The Company has not experienced any losses related to its cash concentration. Investments The Company classifies investments as available-for-sale. The Company’s investments are reported at fair value with unrealized gains and losses, net of taxes, shown as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Investments are recorded as current on the condensed consolidated balance sheets as the invested funds are available for current operations. Management considers available evidence in evaluating potential impairment of investments, including the extent to which fair value is less than cost and adverse conditions related to the security. In the event of a credit loss, an allowance would be recognized to the extent that the fair value of the security is less than the present value of the expected future cash flows. Realized gains and losses on sales of investments are included in investment income in our condensed consolidated statements of operations. Restricted cash and investments The Company holds restricted cash and investments primarily for the future payment of workers’ compensation claims. These investments are categorized as available-for-sale. They are reported at fair value with unrealized gains and losses, net of taxes, shown as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Restricted cash and investments are classified as current and noncurrent on the condensed consolidated balance sheets based on the nature of the restriction. Management considers available evidence in evaluating potential impairment of restricted investments, including the extent to which fair value is less than cost and adverse conditions related to the security. In the event of a credit loss, an allowance would be recognized to the extent that the fair value of the security is less than the present value of the expected future cash flows. Realized gains and losses on sales of restricted investments are included in investment income in our condensed consolidated statements of operations. Restricted cash and investments also includes investments held as part of the Company’s deferred compensation plan. These investments are classified as trading securities and are recorded at fair value with unrealized gains and losses reported as a component of income (loss) from operations. Allowance for doubtful accounts The Company had an allowance for doubtful accounts of $761,000 and $757,000 at June 30, 2021 and December 31, 2020, respectively. We make estimates of the collectability of our accounts receivable for services provided to our customers based on future expected credit losses. Management analyzes historical bad debts, customer concentrations, customer credit-worthiness, current economic trends and changes in customers’ payment trends when evaluating the adequacy of the allowance for doubtful accounts. If the financial condition of our customers deteriorates, resulting in an impairment of their ability to make payments, additional allowances may be required. Workers’ compensation claims liabilities Our workers’ compensation claims liabilities do not represent an exact calculation of liability but rather management’s best estimate, utilizing actuarial expertise and projection techniques, at a given reporting date. The estimated liability for open workers’ compensation claims is based on an evaluation of information provided by our third-party administrator for workers’ compensation claims, coupled with an actuarial estimate of future loss development with respect to reported claims and incurred but not reported claims (together, “IBNR”). Workers’ compensation claims liabilities include case reserve estimates for reported losses, plus additional amounts for estimated IBNR claims, MCC and legal costs, unallocated loss adjustment expenses and estimated future recoveries. The estimate of incurred costs expected to be paid within one year is included in current liabilities, while the estimate of incurred costs expected to be paid beyond one year is included in long-term liabilities on our condensed consolidated balance sheets. These estimates are reviewed at least quarterly and adjustments to estimated liabilities are reflected in current operating results as they become known. The process of arriving at an estimate of unpaid claims and claims adjustment expense involves a high degree of judgment and is affected by both internal and external events, including changes in claims handling practices, changes in reserve estimation procedures, inflation, trends in the litigation and settlement of pending claims, and legislative changes. Our estimates are based on actuarial analysis and informed judgment, derived from individual experience and expertise applied to multiple sets of data and analyses. We consider significant facts and circumstances known both at the time that loss reserves are initially established and as new facts and circumstances become known. Due to the inherent uncertainty underlying loss reserve estimates, the expenses incurred through final resolution of our liability for our workers’ compensation claims will likely vary from the related loss reserves at the reporting date. Therefore, as specific claims are paid out in the future, actual paid losses may be materially different from our current loss reserves. A basic premise in most actuarial analyses is that historical data and past patterns demonstrated in the incurred and paid historical data form a reasonable basis upon which to project future outcomes, absent a material change. Significant structural changes to the available data can materially impact the reserve estimation process. To the extent a material change affecting the ultimate claim liability becomes known, such change is quantified to the extent possible through an analysis of internal Company data and, if available and when appropriate, external data. Nonetheless, actuaries exercise a considerable degree of judgment in the evaluation of these factors and the need for such actuarial judgment is more pronounced when faced with material uncertainties. Safety incentives We accrue for and present expected safety incentives as a reduction of revenue. Customer deposits We require deposits from certain PEO customers to cover a portion of our accounts receivable due from such customers in the event of default of payment. Comprehensive income (loss) Comprehensive income (loss) includes all changes in equity during a period except those that resulted from investments by or distributions to the Company’s stockholders. Other comprehensive income (loss) refers to revenues, expenses, gains and losses that under U.S. generally accepted accounting principles (“GAAP”) are included in comprehensive income (loss), but excluded from net income (loss) as these amounts are recorded directly as an adjustment to stockholders’ equity. Our other comprehensive income (loss) comprises unrealized holding gains and losses on our available-for-sale investments. Statements of cash flows Interest paid during the six months ended June 30, 2021 and 2020 did not materially differ from interest expense. Income taxes paid during the six months ended June 30, 2021 totaled $0.21 million. No income taxes were paid during the Bank deposits and other cash equivalents that are restricted for use are classified as restricted cash. The table below reconciles the cash, cash equivalents and restricted cash balances from our condensed consolidated balance sheets to the amounts reported on the condensed consolidated statements of cash flows (in thousands): June 30, December 31, June 30, December 31, 2021 2020 2020 2019 Cash and cash equivalents $ 2,469 $ 68,688 $ 62,210 $ 44,570 Restricted cash, included in restricted cash and investments 11,694 165,149 93,320 228,771 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 14,163 $ 233,837 $ 155,530 $ 273,341 Basic and diluted earnings per share Basic earnings per share are computed based on the weighted average number of common shares outstanding for each year using the treasury method. Diluted earnings per share reflect the potential effects of the exercise of outstanding stock options, the issuance of stock associated with outstanding restricted stock units, performance share units and the Company’s employee stock purchase plan. Basic and diluted shares outstanding are summarized as follows (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2021 2020 2021 2020 Weighted average number of basic shares outstanding 7,554 7,557 7,565 7,539 Effect of dilutive securities 91 90 93 139 Weighted average number of diluted shares outstanding 7,645 7,647 7,658 7,678 Accounting estimates The preparation of our condensed consolidated financial statements, in conformity with GAAP, requires management to make estimates and assumptions. These affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of revenues and expenses during the reporting periods. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Estimates are used for fair value measurement of investments, allowance for doubtful accounts, deferred income taxes, carrying values for goodwill and property, equipment and software, accrued workers’ compensation liabilities and safety incentive liabilities. Actual results may or may not differ from such estimates.

Fair Value Measurement

Fair Value Measurement	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurement	Note 2 - Fair Value Measurement The following table summarizes the Company’s investments at June 30, 2021 and December 31, 2020 measured at fair value on a recurring basis (in thousands): June 30, 2021 December 31, 2020 Gross Gross Unrealized Unrealized Gains Recorded Gains Recorded Cost (Losses) Basis Cost (Losses) Basis Current: Cash equivalents: Money market funds $ 1,149 $ — $ 1,149 $ 42,007 $ — $ 42,007 Total cash equivalents 1,149 — 1,149 42,007 — 42,007 Investments: Corporate bonds 48,243 541 48,784 50,918 884 51,802 Asset backed securities 36,943 (7 ) 36,936 36,948 (146 ) 36,802 Mortgage backed securities 11,592 (125 ) 11,467 4,367 24 4,391 U.S. government agency securities 7,389 593 7,982 7,396 752 8,148 U.S. treasuries 2,101 14 2,115 100 1 101 Total current investments 106,268 1,016 107,284 99,729 1,515 101,244 Restricted cash and investments (1) Corporate bonds 183,186 1,628 184,814 88,902 4,091 92,993 Mortgage backed securities 88,288 1,470 89,758 48,795 2,356 51,151 U.S. treasuries 69,225 147 69,372 4,371 19 4,390 U.S. government agency securities 34,908 1,909 36,817 29,737 2,466 32,203 Mutual funds 6,121 — 6,121 5,036 — 5,036 Money market funds 396 — 396 40,063 (4 ) 40,059 Asset backed securities 203 2 205 256 4 260 Supranational bonds — — — 4,775 3 4,778 Total restricted cash and investments 382,327 5,156 387,483 221,935 8,935 230,870 Total investments $ 489,744 $ 6,172 $ 495,916 $ 363,671 $ 10,450 $ 374,121 (1) Included in restricted cash and investments within the condensed consolidated balance sheets is restricted cash of $11.5 million and $124.3 million as of June 30, 2021 and December 31, 2020, respectively, which is excluded from the table above. Restricted cash and investments are classified as current and noncurrent on the balance sheet based on the nature of the restriction. The following table summarizes the Company’s investments at June 30, 2021 and December 31, 2020 measured at fair value on a recurring basis by fair value hierarchy level (in thousands): June 30, 2021 December 31, 2020 Total Total Recorded Recorded Basis Level 1 Level 2 Level 3 Other (1) Basis Level 1 Level 2 Level 3 Other (1) Cash equivalents: Money market funds $ 1,149 $ — $ — $ — $ 1,149 $ 42,007 $ — $ — $ — $ 42,007 Investments: Corporate bonds 48,784 — 48,784 — — 51,802 — 51,802 — — Asset backed securities 36,936 — 36,936 — — 36,802 — 36,802 — — Mortgage backed securities 11,467 — 11,467 — — 4,391 — 4,391 — — U.S. government agency securities 7,982 — 7,982 — — 8,148 — 8,148 — — U.S. treasuries 2,115 — 2,115 — — 101 — 101 — — Restricted cash and investments: Corporate bonds 184,814 — 184,814 — — 92,993 — 92,993 — — Mortgage backed securities 89,758 — 89,758 — — 51,151 — 51,151 — — U.S. treasuries 69,372 — 69,372 — — 4,390 — 4,390 — — U.S. government agency securities 36,817 — 36,817 — — 32,203 — 32,203 — — Mutual funds 6,121 6,121 — — — 5,036 5,036 — — — Money market funds 396 — — — 396 40,059 — — — 40,059 Asset backed securities 205 — 205 — — 260 — 260 — — Supranational bonds — — — — — 4,778 — 4,778 — — Total investments $ 495,916 $ 6,121 $ 488,250 $ — $ 1,545 $ 374,121 $ 5,036 $ 287,019 $ — $ 82,066 (1) Investments in money market funds measured at fair value using the net asset value per share practical expedient are not subject to hierarchy level classification disclosure. The Company invests in money market funds that seek to maintain a stable net asset value. These investments include commingled funds that comprise high-quality short-term securities representing liquid debt and monetary instruments where the redemption value is likely to be the fair value. Redemption is permitted daily without written notice. The following table summarizes the contractual maturities of the Company’s available-for-sale securities at June 30, 2021 and December 31, 2020. Actual maturities may differ from contractual maturities because borrowers may have the right to prepay obligations with or without prepayment penalties. June 30, 2021 (In thousands) Less than 1 Year Between 1 to 5 Years Between 5 to 10 Years After 10 Years Total Corporate bonds $ 24,506 $ 67,063 $ 142,029 $ — $ 233,598 U.S. treasuries 1,010 424 70,053 — 71,487 U.S. government agency securities 1,002 18,413 25,384 — 44,799 Asset backed securities — 209 2,201 34,731 37,141 Money market funds $ 1,545 $ — $ — $ — $ 1,545 Total $ 28,063 $ 86,109 $ 239,667 $ 34,731 $ 388,570 December 31, 2020 (In thousands) Less than 1 Year Between 1 to 5 Years Between 5 to 10 Years After 10 Years Total Corporate bonds $ 49,308 $ 61,315 $ 34,172 $ — $ 144,795 Money market funds 82,066 — — — 82,066 U.S. government agency securities 1,013 18,668 20,670 — 40,351 Asset backed securities 2 267 — 36,793 37,062 Supranational bonds 4,778 — — — 4,778 U.S. treasuries 1,367 1,504 1,620 — 4,491 Total $ 138,534 $ 81,754 $ 56,462 $ 36,793 $ 313,543 The average contractual maturity of mortgage backed securities, which are excluded from the table above, was 23 years and 17 years as of June 30, 2021 and December 31, 2020, respectively.

Workers' Compensation Claims

Workers' Compensation Claims	6 Months Ended
	Jun. 30, 2021
Text Block [Abstract]
Workers' Compensation Claims	Note 3 – Workers’ Compensation Claims The following table summarizes the aggregate workers’ compensation reserve activity (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2021 2020 2021 2020 Beginning balance Workers' compensation claims liabilities $ 362,663 $ 445,310 $ 357,746 $ 438,986 Add: claims expense accrual Current period 35,743 32,729 69,013 71,221 Prior periods (5,483 ) (1,373 ) (6,663 ) (2,186 ) 30,260 31,356 62,350 69,035 Less: claim payments related to Current period 3,927 4,527 4,979 6,077 Prior periods (1) 73,240 135,853 99,005 165,530 77,167 140,380 103,984 171,607 Change in claims incurred in excess of retention limits (23 ) 218 (379 ) 90 Ending balance Workers' compensation claims liabilities $ 315,733 $ 336,504 $ 315,733 $ 336,504 Incurred but not reported (IBNR) $ 190,818 $ 206,521 $ 190,818 $ 206,521 Ratio of IBNR to workers' compensation claims liabilities 60 % 61 % 60 % 61 % (1) Insured program The Company provides workers’ compensation coverage for client employees primarily through arrangements with fully licensed, third-party insurers (the “insured program”). Under this program, carriers issue policies to the Company’s clients on behalf of the Company. Approximately 82% of the Company’s workers’ compensation exposure is covered through the insured program. The Company entered into a new arrangement for its insured program effective July 1, 2021 whereby third-party insurers assume all risk of loss for claims incurred after June 30, 2021. The agreement continues to June 30, 2022 and includes a renewal commitment through June 30, 2023. The arrangement allows for premium adjustments depending on overall portfolio performance. If claims develop favorably, BBSI can participate in the savings up to $20.0 million for a twelve-month policy period. If claims develop adversely, additional premium may be charged up to $7.5 million for a twelve-month policy period. For claims incurred under the insured program prior to July 1, 2021, the Company retains risk of loss up to the first $3.0 million per occurrence on policies issued after June 30, 2020 and $5.0 million per occurrence on policies issued before that date. On June 29, 2020, the Company entered into a loss portfolio transfer agreement (“LPT 1”) to remove all outstanding workers’ compensation claims obligations for claims incurred under its insured program between February 1, 2014 and December 31, 2017. This transaction reduced the Company’s outstanding workers’ compensation liabilities and trust account balances by $115.7 million. On June 30, 2021, the Company entered into a loss portfolio transfer agreement (“LPT 2”) to remove all remaining outstanding workers’ compensation claims obligations for client policies issued under its insured program up to June 30, 2018. This transaction reduced the Company’s outstanding workers’ compensation liabilities by $53.1 million. The payment terms of the LPT required $5.0 million to be paid prior to June 30, 2021, with the remaining amount due in July 2021. The balance payable is included in other accrued liabilities on the condensed consolidated balance sheets. The following is a summary of the risk retained by the Company under its insured program after considering the effects of the loss portfolio transfers and current insurance arrangements: Year Claims risk retained 2014 No 2015 No 2016 No 2017 No 2018 (1) No 2019 (1) Yes 2020 Yes 2021 - Through June 30 Yes 2021 - July 1 and after No (1) LPT 2 excluded approximately 10% of claims from 2018 and included an approximately offsetting amount of claims from 2019. The Company is required to maintain minimum collateral levels for policies issued under the insured program, which is held in trust accounts (the “trust accounts”). The balance in the trust accounts was $376.6 million and $290.7 million at June 30, 2021 and December 31, 2020, respectively. The trust account balances are included as a component of the current and long-term restricted cash and investments in the Company’s condensed consolidated balance sheets. Self-insured programs The Company is a self-insured employer with respect to workers' compensation coverage for all employees, including client employees, working in Colorado, Maryland and Oregon. In the state of Washington, state law allows only the Company's staffing services and internal management employees to be covered under the Company's self-insured workers' compensation program. The Company also operates a wholly owned, fully licensed insurance company, Ecole, which provides workers’ compensation coverage to client employees working in Arizona and Utah. Approximately 18% of the Company’s workers’ compensation exposure is covered through self-insurance or Ecole (the “self-insured programs”). For all claims incurred under the Company’s self-insured programs, the Company retains risk of loss up to the first $3.0 million per occurrence, except in Maryland and Colorado, where the Company’s retention per occurrence is $1.0 million and $2.0 million, respectively. For claims incurred under the Company’s self-insured programs prior to July 1, 2020, the Company retains risk of loss up to the first $5.0 million per occurrence, except in Maryland and Colorado, where the retention per occurrence is $1.0 million and $2.0 million, respectively. The states of California, Maryland, Oregon, Washington, Colorado and Delaware required the Company to maintain collateral totaling $58.4 million and $60.1 million at June 30, 2021 and December 31, 2020, respectively, to cover potential workers’ compensation claims losses related to the Company’s current and former status as a self-insured employer. At June 30, 2021, the Company provided surety bonds and standby letters of credit totaling $58.4 million. Claims liabilities The Company provided a total of $315.7 million and $357.7 million at June 30, 2021 and December 31, 2020, respectively, as an estimated future liability for unsettled workers' compensation claims liabilities. Of this amount, $2.5 million and $2.9 million at June 30, 2021 and December 31, 2020, respectively, represent case reserves incurred in excess of the Company’s retention. The accrual for costs incurred in excess of retention limits is offset by a receivable from insurance carriers of $2.5 million and $2.9 million at June 30, 2021 and December 31, 2020, respectively, included in other assets in the condensed consolidated balance sheets.

Revolving Credit Facility and L

Revolving Credit Facility and Long-Term Debt	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Revolving Credit Facility and Long-Term Debt	Note 4 - Revolving Credit Facility and Long-Term Debt The Company maintains an agreement (the “Agreement”) with Wells Fargo Bank, N.A. (the “Bank”) for a revolving credit line of $33.0 million and a sublimit for standby letters of credit of $8.0 million. At June 30, 2021, $6.2 million of the sublimit for standby letters of credit was used. Advances under the revolving credit line bear interest, as selected by the Company, of (a) the daily floating rate of one-month LIBOR plus 1.75% or (b) the fixed rate of LIBOR plus 1.75%. The Agreement also provides for an unused commitment fee of 0.375% per year on the average daily unused amount of the revolving credit line, as well as a fee of 1.75% of the face amount of each letter of credit reserved under the line of credit. The Company had no outstanding borrowings on its revolving credit line at June 30, 2021 and December 31, 2020. The credit facility is collateralized by the Company’s accounts receivable and other rights to receive payment. The Agreement also provide d a $ 63.7 million standby letter of credit (the “ Letter of Credit”). I n April 2021, the Company and the insurance carrier reached an agreement to replace the Letter of Credit with other collateral assets and cancel the Letter of Credit in its entirety. As part of the transaction, the Bank released the $ 38.7 million of collateral held in support of the Letter of Credit, and the Company transferred the $ 38.7 million along with an additional $ 25.0 million to the trust accounts to satisfy the collateral requirements of the insured program. The Agreement requires the satisfaction of certain financial covenants as follows: • EBITDA [net income before taxes plus interest expense (net of capitalized interest expense), depreciation expense, and amortization expense] on a rolling four-quarter basis must be not less than $30 million at the end of each fiscal quarter; and • the ratio of restricted and unrestricted cash and investments to workers’ compensation and safety incentive liabilities must be at least 1.0:1.0 The Agreement imposes certain additional restrictions unless the Bank provides its prior written consent as follows: • incurring additional indebtedness is prohibited, other than purchase financing for the acquisition of assets, provided that the aggregate of all purchase financing does not exceed $1,000,000 at any time; • the Company may not terminate or cancel any of the AICE policies; and • if an event of default would occur, including on a pro forma basis, no dividends or distributions would be permitted to be paid and redemptions and repurchases of the Company’s stock would be permitted only up to $15 million in any rolling 12-month period. The Agreement also contains customary events of default and specified cross-defaults under the Company’s workers’ compensation insurance arrangements. If an event of default under the Agreement occurs and is continuing, the Bank may declare any outstanding obligations under the Agreement to be immediately due and payable. At June 30, 2021, the Company was in compliance with all covenants. The Company maintains a mortgage loan with the Bank with a balance of approximately $3.6 million and $3.7 million at June 30, 2021 and December 31, 2020, respectively, secured by the Company’s corporate office building in Vancouver, Washington. This loan requires payment of monthly installments of $18,375, bearing interest at the

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Note 5 – Income Taxes Under ASC 740, “Income Taxes,” management evaluates the realizability of the deferred tax assets on a quarterly basis under a “more likely than not” standard. As part of this evaluation, management reviews all evidence, both positive and negative, to determine if a valuation allowance is needed. One component of this analysis is to determine whether the Company was in a cumulative loss position for the most recent 12 quarters. The Company was in a cumulative income position for the 12 quarters ended June 30, 2021. The Company’s realization of a portion of net deferred tax assets is based in part on our estimates of the timing of reversals of certain temporary differences and on the generation of taxable income before such reversals. The Company is subject to income taxes in U.S. federal and multiple state and local tax jurisdictions. The Internal Revenue Service is examining the Company’s federal tax returns for the years ended December 31, 2011, 2012, 2013 and 2014. In July 2020, BBSI received notice that the IRS intends to disallow certain wage-based tax credits claimed for years 2011 to 2014, which would result in an estimated total additional tax due of approximately $2.3 million for the tax years 2012 through 2015, including the impact on carryover tax attributes. The Company disagrees with the IRS determination and believes that it has technical merits to defend its position. Based on management’s more-likely-than-not assessment that the position is sustainable, no reserve for the aforementioned IRS notice of disallowance of wage-based tax credits has been recorded in the financial statements. In July 2021, the Company received a notice from the IRS indicating the IRS plans to audit the Company’s federal tax returns for the years ended December 31, 2017, 2018, and 2019. In the major jurisdictions where it operates, the Company is generally no longer subject to income tax examinations by tax authorities for the 2015 and 2016 tax year and tax years before 2011. As of June 30, 2021, the Company had no material unrecognized tax benefits. A portion of the consolidated income the Company generates is not subject to state income tax. Depending on the percentage of this income as compared to total consolidated income, the Company's state effective tax rate could fluctuate from expectations.

Litigation

Litigation	6 Months Ended
	Jun. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Litigation	Note 6 – Litigation On November 21, 2012, David Kaanaana (“Kaanaana”), a former staffing employee, filed a class action wage and hour lawsuit against BBSI in the California Superior Court on behalf of himself and certain other employees who worked at County Sanitation District No. 2 of Los Angeles County (“the District”). The trial court ruled in plaintiffs’ favor regarding certain alleged meal breach violations but ruled in favor of BBSI with respect to the application of the California prevailing wage law to the District and other claims. These latter rulings were appealed by the plaintiffs to the California Court of Appeal. On November 30, 2018, the California Court of Appeal for the Second Appellate District returned its decision in Kaanaana v. Barrett Business Services, Inc., overruling the trial court's decision to dismiss the prevailing wage claim, ruling that the work in question at the District constitutes “public works” under the applicable law, and also ruling that plaintiffs’ are entitled to additional remedies with regard to the meal break violations under California law. On January 9, 2019, BBSI filed a petition of review to the California Supreme Court. On February 27, 2019, the California Supreme Court granted the petition to review the Court of Appeal’s decision with respect to the prevailing wage issue. An amicus brief in support of BBSI’s appeal was filed by the District and certain associations of special districts, cities and counties in California. Oral argument took place on January 5, 2021. A decision from the California Supreme Court was issued March 29, 2021 affirming the Court of Appeal decision and concluding that the recycling sorting work performed by the staffing employees in question was a “public work” and therefore would be subject to prevailing wage requirements. No damages were awarded in the appeals process. The case has been remanded to Superior Court for any such determination with respect to both the prevailing wage issue and any additional remedies for the meal break violations. Although certain costs from the Kaanaana case are estimable and accrued, potential liability from the public work determination is not currently considered estimable and is therefore not accrued. There is not precedent on how this type of ruling would impact historical work performed prior to a relevant prevailing wage rate being established by the California Department of Industrial Relations. There remain many possible outcomes, including that a prevailing wage rate could be set considerably higher than actual wages paid, which totaled approximately $2.2 million, or that actual wages paid may be determined to be equivalent to prevailing wages. There may also be other procedural outcomes. BBSI believes it has the right to recover from the District any increased costs that may result from the court’s past or future decisions related to prevailing wage requirements, including any fees and penalties that may be incurred. In addition to the matter above, BBSI is subject to other legal proceedings and claims that arise in the ordinary course of our business. There are significant uncertainties surrounding litigation, including the possible liabilities in the Kaanaana case. For this case and others, management has recorded estimated liabilities of $3.8 million in other accrued liabilities in the condensed consolidated balance sheets.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	Note 7 – Subsequent Events We have evaluated events and transactions occurring after the balance sheet date through our filing date and noted no events that are subject to recognition or disclosure.

Basis of Presentation of Inte_2

Basis of Presentation of Interim Period Statements (Policies)	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Revenue recognition	Revenue recognition Professional employer (“PEO”) services are normally used by organizations to satisfy ongoing needs related to the management of human capital and are governed by the terms of a client services agreement which covers all employees at a particular work site. Staffing revenues relate primarily to short-term staffing, contract staffing and on-site management services. The Company’s performance obligations for PEO and staffing services are satisfied, and the related revenue is recognized, as services are rendered by our workforce. Our PEO client service agreements have a minimum term of one year, are renewable on an annual basis, and typically require 30 days’ written notice to cancel or terminate the contract by either party. In addition, our client service agreements provide for immediate termination upon any default of the client regardless of when notice is given. PEO customers are invoiced following the end of each payroll processing cycle, with payment generally due on the invoice date. Staffing customers are generally invoiced weekly based on agreed rates per employee and actual hours worked, typically with payment terms of 30 days. The amount of earned but unbilled revenue is classified as a receivable on the condensed consolidated balance sheets. We report PEO revenues net of direct payroll costs because we are not the primary obligor for these payments to our clients’ employees. Direct payroll costs include salaries, wages, health insurance, and employee out-of-pocket expenses incurred incidental to employment. We also present revenue net of safety incentives because these incentives represent consideration payable to customers.
Cost of revenues	Cost of revenues Our cost of revenues for PEO services includes employer payroll-related taxes and workers’ compensation costs. Our cost of revenues for staffing services includes direct payroll costs, employer payroll-related taxes, employee benefits, and workers’ compensation costs. Direct payroll costs represent the gross payroll earned by staffing services employees based on salary or hourly wages. Payroll taxes and employee benefits consist of the employer’s portion of Social Security and Medicare taxes, federal and state unemployment taxes, and staffing services employee reimbursements for materials, supplies and other expenses, which are paid by our customer. Workers’ compensation costs consist primarily of claims reserves, claims administration fees, legal fees, medical cost containment (“MCC”) expense, state administrative agency fees, third-party broker commissions, risk manager payroll, premiums for excess insurance, and the insured program, as well as costs associated with operating our two wholly owned insurance companies, Associated Insurance Company for Excess (“AICE”) and Ecole Insurance Company (“Ecole”).
Cash and cash equivalents	Cash and cash equivalents We consider non-restricted short-term investments that are highly liquid, readily convertible into cash, and have maturities at acquisition of less than three months, to be cash equivalents for purposes of the condensed consolidated statements of cash flows and condensed consolidated balance sheets. The Company maintains cash balances in bank accounts that normally exceed FDIC insured limits. The Company has not experienced any losses related to its cash concentration.
Investments	Investments The Company classifies investments as available-for-sale. The Company’s investments are reported at fair value with unrealized gains and losses, net of taxes, shown as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Investments are recorded as current on the condensed consolidated balance sheets as the invested funds are available for current operations. Management considers available evidence in evaluating potential impairment of investments, including the extent to which fair value is less than cost and adverse conditions related to the security. In the event of a credit loss, an allowance would be recognized to the extent that the fair value of the security is less than the present value of the expected future cash flows. Realized gains and losses on sales of investments are included in investment income in our condensed consolidated statements of operations.
Restricted cash and investments	Restricted cash and investments The Company holds restricted cash and investments primarily for the future payment of workers’ compensation claims. These investments are categorized as available-for-sale. They are reported at fair value with unrealized gains and losses, net of taxes, shown as a component of accumulated other comprehensive income (loss) in stockholders’ equity. Restricted cash and investments are classified as current and noncurrent on the condensed consolidated balance sheets based on the nature of the restriction. Management considers available evidence in evaluating potential impairment of restricted investments, including the extent to which fair value is less than cost and adverse conditions related to the security. In the event of a credit loss, an allowance would be recognized to the extent that the fair value of the security is less than the present value of the expected future cash flows. Realized gains and losses on sales of restricted investments are included in investment income in our condensed consolidated statements of operations. Restricted cash and investments also includes investments held as part of the Company’s deferred compensation plan. These investments are classified as trading securities and are recorded at fair value with unrealized gains and losses reported as a component of income (loss) from operations.
Allowance for doubtful accounts	Allowance for doubtful accounts The Company had an allowance for doubtful accounts of $761,000 and $757,000 at June 30, 2021 and December 31, 2020, respectively. We make estimates of the collectability of our accounts receivable for services provided to our customers based on future expected credit losses. Management analyzes historical bad debts, customer concentrations, customer credit-worthiness, current economic trends and changes in customers’ payment trends when evaluating the adequacy of the allowance for doubtful accounts. If the financial condition of our customers deteriorates, resulting in an impairment of their ability to make payments, additional allowances may be required.
Workers' compensation claims liabilities	Workers’ compensation claims liabilities Our workers’ compensation claims liabilities do not represent an exact calculation of liability but rather management’s best estimate, utilizing actuarial expertise and projection techniques, at a given reporting date. The estimated liability for open workers’ compensation claims is based on an evaluation of information provided by our third-party administrator for workers’ compensation claims, coupled with an actuarial estimate of future loss development with respect to reported claims and incurred but not reported claims (together, “IBNR”). Workers’ compensation claims liabilities include case reserve estimates for reported losses, plus additional amounts for estimated IBNR claims, MCC and legal costs, unallocated loss adjustment expenses and estimated future recoveries. The estimate of incurred costs expected to be paid within one year is included in current liabilities, while the estimate of incurred costs expected to be paid beyond one year is included in long-term liabilities on our condensed consolidated balance sheets. These estimates are reviewed at least quarterly and adjustments to estimated liabilities are reflected in current operating results as they become known. The process of arriving at an estimate of unpaid claims and claims adjustment expense involves a high degree of judgment and is affected by both internal and external events, including changes in claims handling practices, changes in reserve estimation procedures, inflation, trends in the litigation and settlement of pending claims, and legislative changes. Our estimates are based on actuarial analysis and informed judgment, derived from individual experience and expertise applied to multiple sets of data and analyses. We consider significant facts and circumstances known both at the time that loss reserves are initially established and as new facts and circumstances become known. Due to the inherent uncertainty underlying loss reserve estimates, the expenses incurred through final resolution of our liability for our workers’ compensation claims will likely vary from the related loss reserves at the reporting date. Therefore, as specific claims are paid out in the future, actual paid losses may be materially different from our current loss reserves. A basic premise in most actuarial analyses is that historical data and past patterns demonstrated in the incurred and paid historical data form a reasonable basis upon which to project future outcomes, absent a material change. Significant structural changes to the available data can materially impact the reserve estimation process. To the extent a material change affecting the ultimate claim liability becomes known, such change is quantified to the extent possible through an analysis of internal Company data and, if available and when appropriate, external data. Nonetheless, actuaries exercise a considerable degree of judgment in the evaluation of these factors and the need for such actuarial judgment is more pronounced when faced with material uncertainties.
Safety incentives	Safety incentives We accrue for and present expected safety incentives as a reduction of revenue.
Customer deposits	Customer deposits We require deposits from certain PEO customers to cover a portion of our accounts receivable due from such customers in the event of default of payment.
Comprehensive income (loss)	Comprehensive income (loss) Comprehensive income (loss) includes all changes in equity during a period except those that resulted from investments by or distributions to the Company’s stockholders. Other comprehensive income (loss) refers to revenues, expenses, gains and losses that under U.S. generally accepted accounting principles (“GAAP”) are included in comprehensive income (loss), but excluded from net income (loss) as these amounts are recorded directly as an adjustment to stockholders’ equity. Our other comprehensive income (loss) comprises unrealized holding gains and losses on our available-for-sale investments.
Statements of cash flows	Statements of cash flows Interest paid during the six months ended June 30, 2021 and 2020 did not materially differ from interest expense. Income taxes paid during the six months ended June 30, 2021 totaled $0.21 million. No income taxes were paid during the Bank deposits and other cash equivalents that are restricted for use are classified as restricted cash. The table below reconciles the cash, cash equivalents and restricted cash balances from our condensed consolidated balance sheets to the amounts reported on the condensed consolidated statements of cash flows (in thousands): June 30, December 31, June 30, December 31, 2021 2020 2020 2019 Cash and cash equivalents $ 2,469 $ 68,688 $ 62,210 $ 44,570 Restricted cash, included in restricted cash and investments 11,694 165,149 93,320 228,771 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 14,163 $ 233,837 $ 155,530 $ 273,341
Basic and diluted earnings per share	Basic and diluted earnings per share Basic earnings per share are computed based on the weighted average number of common shares outstanding for each year using the treasury method. Diluted earnings per share reflect the potential effects of the exercise of outstanding stock options, the issuance of stock associated with outstanding restricted stock units, performance share units and the Company’s employee stock purchase plan. Basic and diluted shares outstanding are summarized as follows (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2021 2020 2021 2020 Weighted average number of basic shares outstanding 7,554 7,557 7,565 7,539 Effect of dilutive securities 91 90 93 139 Weighted average number of diluted shares outstanding 7,645 7,647 7,658 7,678
Accounting estimates	Accounting estimates The preparation of our condensed consolidated financial statements, in conformity with GAAP, requires management to make estimates and assumptions. These affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of revenues and expenses during the reporting periods. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Estimates are used for fair value measurement of investments, allowance for doubtful accounts, deferred income taxes, carrying values for goodwill and property, equipment and software, accrued workers’ compensation liabilities and safety incentive liabilities. Actual results may or may not differ from such estimates.

Basis of Presentation of Inte_3

Basis of Presentation of Interim Period Statements (Tables)	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Reconciles of Cash, Cash Equivalents and Restricted Cash Balances	The table below reconciles the cash, cash equivalents and restricted cash balances from our condensed consolidated balance sheets to the amounts reported on the condensed consolidated statements of cash flows (in thousands): June 30, December 31, June 30, December 31, 2021 2020 2020 2019 Cash and cash equivalents $ 2,469 $ 68,688 $ 62,210 $ 44,570 Restricted cash, included in restricted cash and investments 11,694 165,149 93,320 228,771 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 14,163 $ 233,837 $ 155,530 $ 273,341
Summary of Basic and Diluted Common Shares Outstanding	Basic and diluted shares outstanding are summarized as follows (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2021 2020 2021 2020 Weighted average number of basic shares outstanding 7,554 7,557 7,565 7,539 Effect of dilutive securities 91 90 93 139 Weighted average number of diluted shares outstanding 7,645 7,647 7,658 7,678

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Summary of Investments Measured at Fair Value on Recurring Basis	The following table summarizes the Company’s investments at June 30, 2021 and December 31, 2020 measured at fair value on a recurring basis (in thousands): June 30, 2021 December 31, 2020 Gross Gross Unrealized Unrealized Gains Recorded Gains Recorded Cost (Losses) Basis Cost (Losses) Basis Current: Cash equivalents: Money market funds $ 1,149 $ — $ 1,149 $ 42,007 $ — $ 42,007 Total cash equivalents 1,149 — 1,149 42,007 — 42,007 Investments: Corporate bonds 48,243 541 48,784 50,918 884 51,802 Asset backed securities 36,943 (7 ) 36,936 36,948 (146 ) 36,802 Mortgage backed securities 11,592 (125 ) 11,467 4,367 24 4,391 U.S. government agency securities 7,389 593 7,982 7,396 752 8,148 U.S. treasuries 2,101 14 2,115 100 1 101 Total current investments 106,268 1,016 107,284 99,729 1,515 101,244 Restricted cash and investments (1) Corporate bonds 183,186 1,628 184,814 88,902 4,091 92,993 Mortgage backed securities 88,288 1,470 89,758 48,795 2,356 51,151 U.S. treasuries 69,225 147 69,372 4,371 19 4,390 U.S. government agency securities 34,908 1,909 36,817 29,737 2,466 32,203 Mutual funds 6,121 — 6,121 5,036 — 5,036 Money market funds 396 — 396 40,063 (4 ) 40,059 Asset backed securities 203 2 205 256 4 260 Supranational bonds — — — 4,775 3 4,778 Total restricted cash and investments 382,327 5,156 387,483 221,935 8,935 230,870 Total investments $ 489,744 $ 6,172 $ 495,916 $ 363,671 $ 10,450 $ 374,121 (1) Included in restricted cash and investments within the condensed consolidated balance sheets is restricted cash of $11.5 million and $124.3 million as of June 30, 2021 and December 31, 2020, respectively, which is excluded from the table above. Restricted cash and investments are classified as current and noncurrent on the balance sheet based on the nature of the restriction.
Summary of Assets Measured at Fair Value on Recurring Basis	The following table summarizes the Company’s investments at June 30, 2021 and December 31, 2020 measured at fair value on a recurring basis by fair value hierarchy level (in thousands): June 30, 2021 December 31, 2020 Total Total Recorded Recorded Basis Level 1 Level 2 Level 3 Other (1) Basis Level 1 Level 2 Level 3 Other (1) Cash equivalents: Money market funds $ 1,149 $ — $ — $ — $ 1,149 $ 42,007 $ — $ — $ — $ 42,007 Investments: Corporate bonds 48,784 — 48,784 — — 51,802 — 51,802 — — Asset backed securities 36,936 — 36,936 — — 36,802 — 36,802 — — Mortgage backed securities 11,467 — 11,467 — — 4,391 — 4,391 — — U.S. government agency securities 7,982 — 7,982 — — 8,148 — 8,148 — — U.S. treasuries 2,115 — 2,115 — — 101 — 101 — — Restricted cash and investments: Corporate bonds 184,814 — 184,814 — — 92,993 — 92,993 — — Mortgage backed securities 89,758 — 89,758 — — 51,151 — 51,151 — — U.S. treasuries 69,372 — 69,372 — — 4,390 — 4,390 — — U.S. government agency securities 36,817 — 36,817 — — 32,203 — 32,203 — — Mutual funds 6,121 6,121 — — — 5,036 5,036 — — — Money market funds 396 — — — 396 40,059 — — — 40,059 Asset backed securities 205 — 205 — — 260 — 260 — — Supranational bonds — — — — — 4,778 — 4,778 — — Total investments $ 495,916 $ 6,121 $ 488,250 $ — $ 1,545 $ 374,121 $ 5,036 $ 287,019 $ — $ 82,066 (1) Investments in money market funds measured at fair value using the net asset value per share practical expedient are not subject to hierarchy level classification disclosure. The Company invests in money market funds that seek to maintain a stable net asset value. These investments include commingled funds that comprise high-quality short-term securities representing liquid debt and monetary instruments where the redemption value is likely to be the fair value. Redemption is permitted daily without written notice.
Summary of Contractual Maturities of Available for Sale Securities	The following table summarizes the contractual maturities of the Company’s available-for-sale securities at June 30, 2021 and December 31, 2020. Actual maturities may differ from contractual maturities because borrowers may have the right to prepay obligations with or without prepayment penalties. June 30, 2021 (In thousands) Less than 1 Year Between 1 to 5 Years Between 5 to 10 Years After 10 Years Total Corporate bonds $ 24,506 $ 67,063 $ 142,029 $ — $ 233,598 U.S. treasuries 1,010 424 70,053 — 71,487 U.S. government agency securities 1,002 18,413 25,384 — 44,799 Asset backed securities — 209 2,201 34,731 37,141 Money market funds $ 1,545 $ — $ — $ — $ 1,545 Total $ 28,063 $ 86,109 $ 239,667 $ 34,731 $ 388,570 December 31, 2020 (In thousands) Less than 1 Year Between 1 to 5 Years Between 5 to 10 Years After 10 Years Total Corporate bonds $ 49,308 $ 61,315 $ 34,172 $ — $ 144,795 Money market funds 82,066 — — — 82,066 U.S. government agency securities 1,013 18,668 20,670 — 40,351 Asset backed securities 2 267 — 36,793 37,062 Supranational bonds 4,778 — — — 4,778 U.S. treasuries 1,367 1,504 1,620 — 4,491 Total $ 138,534 $ 81,754 $ 56,462 $ 36,793 $ 313,543

Workers' Compensation Claims (T

Workers' Compensation Claims (Tables)	6 Months Ended
	Jun. 30, 2021
Text Block [Abstract]
Summarizes Aggregate Workers' Compensation Reserve Activity	The following table summarizes the aggregate workers’ compensation reserve activity (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2021 2020 2021 2020 Beginning balance Workers' compensation claims liabilities $ 362,663 $ 445,310 $ 357,746 $ 438,986 Add: claims expense accrual Current period 35,743 32,729 69,013 71,221 Prior periods (5,483 ) (1,373 ) (6,663 ) (2,186 ) 30,260 31,356 62,350 69,035 Less: claim payments related to Current period 3,927 4,527 4,979 6,077 Prior periods (1) 73,240 135,853 99,005 165,530 77,167 140,380 103,984 171,607 Change in claims incurred in excess of retention limits (23 ) 218 (379 ) 90 Ending balance Workers' compensation claims liabilities $ 315,733 $ 336,504 $ 315,733 $ 336,504 Incurred but not reported (IBNR) $ 190,818 $ 206,521 $ 190,818 $ 206,521 Ratio of IBNR to workers' compensation claims liabilities 60 % 61 % 60 % 61 % (1)
Summary of Risk Retained by Insured Program after Considering Loss Portfolio Transfers and Current Insurance Arrangements	The following is a summary of the risk retained by the Company under its insured program after considering the effects of the loss portfolio transfers and current insurance arrangements: Year Claims risk retained 2014 No 2015 No 2016 No 2017 No 2018 (1) No 2019 (1) Yes 2020 Yes 2021 - Through June 30 Yes 2021 - July 1 and after No (1) LPT 2 excluded approximately 10% of claims from 2018 and included an approximately offsetting amount of claims from 2019.

Basis of Presentation of Inte_4

Basis of Presentation of Interim Period Statements - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2021USD ($)Company	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Revenue recognition professional employer service contracts term	1 year
Professional employer service contract cancellation and termination period	30 days
Payment term for staffing customers	30 days
Number of wholly-owned insurance companies | Company	2
Cash and cash equivalents, maturity term	3 months
Allowance for doubtful accounts	$ 761,000		$ 757,000
Estimate of liability for unpaid safety incentives	6,900,000		$ 18,800,000
Income taxes paid	$ 210,000	$ 0

Basis of Presentation of Inte_5

Basis of Presentation of Interim Period Statements - Schedule of Reconciles of Cash, Cash Equivalents and Restricted Cash Balances (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 2,469	$ 68,688	$ 62,210	$ 44,570
Restricted cash, included in restricted cash and investments	11,694	165,149	93,320	228,771
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 14,163	$ 233,837	$ 155,530	$ 273,341

Basis of Presentation of Inte_6

Basis of Presentation of Interim Period Statements - Summary of Basic and Diluted Common Shares Outstanding (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Weighted Average Number Of Shares Outstanding Diluted Disclosure Items [Abstract]
Weighted average number of basic shares outstanding	7,554	7,557	7,565	7,539
Effect of dilutive securities	91	90	93	139
Weighted average number of diluted shares outstanding	7,645	7,647	7,658	7,678

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	$ 489,744	$ 363,671
Gross Unrealized Gains (Losses)	6,172	10,450
Recorded Basis	495,916	374,121
Investments Current [Member] | Cash and Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	1,149	42,007
Recorded Basis	1,149	42,007
Investments Current [Member] | Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	1,149	42,007
Recorded Basis	1,149	42,007
Investments Current [Member] | Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	106,268	99,729
Gross Unrealized Gains (Losses)	1,016	1,515
Recorded Basis	107,284	101,244
Investments Current [Member] | Investments [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	48,243	50,918
Gross Unrealized Gains (Losses)	541	884
Recorded Basis	48,784	51,802
Investments Current [Member] | Investments [Member] | Asset Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	36,943	36,948
Gross Unrealized Gains (Losses)	(7)	(146)
Recorded Basis	36,936	36,802
Investments Current [Member] | Investments [Member] | U.S. Government Agency Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	7,389	7,396
Gross Unrealized Gains (Losses)	593	752
Recorded Basis	7,982	8,148
Investments Current [Member] | Investments [Member] | U.S. Treasuries [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	2,101	100
Gross Unrealized Gains (Losses)	14	1
Recorded Basis	2,115	101
Investments Current [Member] | Investments [Member] | Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	11,592	4,367
Gross Unrealized Gains (Losses)	(125)	24
Recorded Basis	11,467	4,391
Investments Noncurrent [Member] | Restricted Cash and Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	382,327	221,935
Gross Unrealized Gains (Losses)	5,156	8,935
Recorded Basis	387,483	230,870
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	396	40,063
Gross Unrealized Gains (Losses)		(4)
Recorded Basis	396	40,059
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	183,186	88,902
Gross Unrealized Gains (Losses)	1,628	4,091
Recorded Basis	184,814	92,993
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Asset Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	203	256
Gross Unrealized Gains (Losses)	2	4
Recorded Basis	205	260
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | U.S. Government Agency Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	34,908	29,737
Gross Unrealized Gains (Losses)	1,909	2,466
Recorded Basis	36,817	32,203
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | U.S. Treasuries [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	69,225	4,371
Gross Unrealized Gains (Losses)	147	19
Recorded Basis	69,372	4,390
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	88,288	48,795
Gross Unrealized Gains (Losses)	1,470	2,356
Recorded Basis	89,758	51,151
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	6,121	5,036
Recorded Basis	$ 6,121	5,036
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Supranational Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost		4,775
Gross Unrealized Gains (Losses)		3
Recorded Basis		$ 4,778

Fair Value Measurement - Summ_2

Fair Value Measurement - Summary of Investments Measured at Fair Value on Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Restricted cash	$ 11.5	$ 124.3

Fair Value Measurement - Summ_3

Fair Value Measurement - Summary of Assets Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	$ 495,916	$ 374,121
Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	1,545	82,066
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	6,121	5,036
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	488,250	287,019
Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	1,149	42,007
Cash and Cash Equivalents [Member] | Money Market Funds [Member] | Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	1,149	42,007
Investments [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	48,784	51,802
Investments [Member] | Corporate Bonds [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	48,784	51,802
Investments [Member] | Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	11,467	4,391
Investments [Member] | Mortgage Backed Securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	11,467	4,391
Investments [Member] | U.S. Treasuries [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	2,115	101
Investments [Member] | U.S. Treasuries [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	2,115	101
Investments [Member] | U.S. Government Agency Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	7,982	8,148
Investments [Member] | U.S. Government Agency Securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	7,982	8,148
Investments [Member] | Asset Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	36,936	36,802
Investments [Member] | Asset Backed Securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	36,936	36,802
Restricted Cash and Investments [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	396	40,059
Restricted Cash and Investments [Member] | Money Market Funds [Member] | Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	396	40,059
Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	184,814	92,993
Restricted Cash and Investments [Member] | Corporate Bonds [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	184,814	92,993
Restricted Cash and Investments [Member] | Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	89,758	51,151
Restricted Cash and Investments [Member] | Mortgage Backed Securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	89,758	51,151
Restricted Cash and Investments [Member] | U.S. Treasuries [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	69,372	4,390
Restricted Cash and Investments [Member] | U.S. Treasuries [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	69,372	4,390
Restricted Cash and Investments [Member] | U.S. Government Agency Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	36,817	32,203
Restricted Cash and Investments [Member] | U.S. Government Agency Securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	36,817	32,203
Restricted Cash and Investments [Member] | Asset Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	205	260
Restricted Cash and Investments [Member] | Asset Backed Securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	205	260
Restricted Cash and Investments [Member] | Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	6,121	5,036
Restricted Cash and Investments [Member] | Mutual Funds [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	$ 6,121	5,036
Restricted Cash and Investments [Member] | Supranational Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis		4,778
Restricted Cash and Investments [Member] | Supranational Bonds [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis		$ 4,778

Fair Value Measurement - Summ_4

Fair Value Measurement - Summary of Contractual Maturities of Available for Sale Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	$ 28,063	$ 138,534
Available for sale securities, contractual maturities between 1 to 5 years	86,109	81,754
Available for sale securities, contractual maturities between 5 to 10 years	239,667	56,462
Available for sale securities, contractual maturities after 10 years	34,731	36,793
Available for sale securities, contractual maturities, Total	388,570	313,543
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	24,506	49,308
Available for sale securities, contractual maturities between 1 to 5 years	67,063	61,315
Available for sale securities, contractual maturities between 5 to 10 years	142,029	34,172
Available for sale securities, contractual maturities, Total	233,598	144,795
Money Market Funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	1,545	82,066
Available for sale securities, contractual maturities, Total	1,545	82,066
U.S. Government Agency Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	1,002	1,013
Available for sale securities, contractual maturities between 1 to 5 years	18,413	18,668
Available for sale securities, contractual maturities between 5 to 10 years	25,384	20,670
Available for sale securities, contractual maturities, Total	44,799	40,351
Asset Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year		2
Available for sale securities, contractual maturities between 1 to 5 years	209	267
Available for sale securities, contractual maturities between 5 to 10 years	2,201
Available for sale securities, contractual maturities after 10 years	34,731	36,793
Available for sale securities, contractual maturities, Total	37,141	37,062
U.S. Treasuries [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	1,010	1,367
Available for sale securities, contractual maturities between 1 to 5 years	424	1,504
Available for sale securities, contractual maturities between 5 to 10 years	70,053	1,620
Available for sale securities, contractual maturities, Total	$ 71,487	4,491
Supranational Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year		4,778
Available for sale securities, contractual maturities, Total		$ 4,778

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail)	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Average contractual maturity period	23 years	17 years

Workers' Compensation Claims -

Workers' Compensation Claims - Summarizes Aggregate Workers' Compensation Reserve Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Workers Compensation Reserve [Abstract]
Workers' compensation claims liabilities, Beginning balance	$ 362,663	$ 445,310	$ 357,746	$ 438,986
Add: claims expense accrual
Current period	35,743	32,729	69,013	71,221
Prior periods	(5,483)	(1,373)	(6,663)	(2,186)
Total expense accrual	30,260	31,356	62,350	69,035
Less: claim payments related to
Current period	3,927	4,527	4,979	6,077
Prior periods	73,240	135,853	99,005	165,530
Total paid	77,167	140,380	103,984	171,607
Change in claims incurred in excess of retention limits	(23)	218	(379)	90
Workers' compensation claims liabilities, Ending balance	315,733	336,504	315,733	336,504
Incurred but not reported (IBNR)	$ 190,818	$ 206,521	$ 190,818	$ 206,521
Ratio of IBNR to workers' compensation claims liabilities	60.00%	61.00%	60.00%	61.00%

Workers' Compensation Claims _2

Workers' Compensation Claims - Summarizes Aggregate Workers' Compensation Reserve Activity (Parenthetical) (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)
Third-party Insurance Carrier [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claim payments related to prior period includes amount payable	$ 47.4

Workers' Compensation Claims _3

Workers' Compensation Claims - Additional Information (Detail) - USD ($)	Jul. 01, 2021	Jun. 29, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Description of renewed agreement			The Company entered into a new arrangement for its insured program effective July 1, 2021 whereby third-party insurers assume all risk of loss for claims incurred after June 30, 2021. The agreement continues to June 30, 2022 and includes a renewal commitment through June 30, 2023. The arrangement allows for premium adjustments depending on overall portfolio performance. If claims develop favorably, BBSI can participate in the savings up to $20.0 million for a twelve-month policy period. If claims develop adversely, additional premium may be charged up to $7.5 million for a twelve-month policy period.
Maximum savings amount for twelve month policy period, if claims develop favorably			$ 20,000,000
Maximum additional premium charged amount for twelve month policy period, if claims develop adversely			7,500,000
Balance in Chubb trust accounts		$ 115,700,000	376,600,000		$ 290,700,000
Workers compensation liability			315,733,000	$ 336,504,000	357,746,000	$ 362,663,000	$ 445,310,000	$ 438,986,000
Workers compensation liability, current			86,047,000		102,040,000
Collateral securities maintain to cover potential workers compensation claims losses			58,400,000		60,100,000
Surety bonds and standby letters of credit			58,400,000
Reserves incurred in excess of retention limits			2,500,000		2,900,000
Other Assets [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accrual for costs incurred in excess of retention limits offset by a receivable			$ 2,500,000		$ 2,900,000
Insured Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of worker's compensation exposure covered			82.00%
Worker's compensation risk claim maximum		$ 5,000,000
Workers compensation liability			$ 53,100,000
Workers compensation liability, current			$ 5,000,000
Insured Program [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Worker's compensation risk claim maximum	$ 3,000,000
Self Insured Programs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of worker's compensation exposure covered			18.00%
Worker's compensation risk claim maximum			$ 3,000,000	5,000,000
Self Insured Programs [Member] | Maryland [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reinsurance coverage			1,000,000	1,000,000
Self Insured Programs [Member] | Colorado [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reinsurance coverage			$ 2,000,000	$ 2,000,000

Worker's Compensation Claims -

Worker's Compensation Claims - Summary of Risk Retained by Insured Program after Considering Loss Portfolio Transfers and Current Insurance Arrangements (Details)	12 Months Ended
	Jun. 30, 2021
2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claims risk retained	No
2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claims risk retained	No
2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claims risk retained	No
2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claims risk retained	No
2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claims risk retained	No
2019 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claims risk retained	Yes
2020 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claims risk retained	Yes
2021 - Through June 30 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claims risk retained	Yes
2021 - July 1 and after [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Claims risk retained	No

Worker's Compensation Claims _2

Worker's Compensation Claims - Summary of Risk Retained by Insured Program after Considering Loss Portfolio Transfers and Current Insurance Arrangements (Parenthetical) (Details)	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Percentage of claim excluded	10.00%

Revolving Credit Facility and_2

Revolving Credit Facility and Long-Term Debt - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended				6 Months Ended
	Apr. 30, 2021	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Dec. 31, 2020	Jun. 29, 2020
Line of Credit Facility [Line Items]
Balance in Chubb trust accounts				$ 376,600,000		$ 376,600,000	$ 290,700,000	$ 115,700,000
Agreement [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing used				6,200,000		$ 6,200,000
Line of credit facility commitment fee description						The Agreement also provides for an unused commitment fee of 0.375% per year on the average daily unused amount of the revolving credit line, as well as a fee of 1.75% of the face amount of each letter of credit reserved under the line of credit.
Outstanding balance on term loan and revolving credit facility				$ 0		$ 0	0
Balance in Chubb trust accounts	$ 25,000,000
Ratio of restricted and unrestricted cash and investments to workers' compensation and claim liabilities				1.00%	1.00%
Dividends or distributions paid						0
Maximum amount to redeem retire repurchase or acquire stock upon agreement						15,000,000
Agreement [Member] | Scenario Forecast [Member]
Line of Credit Facility [Line Items]
Ratio of restricted and unrestricted cash and investments to workers' compensation and claim liabilities		1.00%	1.00%
Agreement [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
EBITDA				$ 30,000,000	$ 30,000,000	30,000,000
Agreement [Member] | Minimum [Member] | Scenario Forecast [Member]
Line of Credit Facility [Line Items]
EBITDA		$ 30,000,000	$ 30,000,000
Agreement [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Prohibition on incurring additional indebtedness without the prior approval of the Bank in purchase money financing						1,000,000
Agreement [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity				33,000,000		$ 33,000,000
Unused commitment fee on unused amount during period						0.375%
Agreement [Member] | Revolving Credit Facility [Member] | Daily Floating Rate [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description						the daily floating rate of one-month LIBOR plus 1.75% or (b) the fixed rate of LIBOR plus 1.75%
LIBOR plus rate						1.75%
Agreement [Member] | Revolving Credit Facility [Member] | Fixed Rate [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description						the fixed rate of LIBOR plus 1.75%
LIBOR plus rate						1.75%
Agreement [Member] | Standby Letters of Credit [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity				8,000,000		$ 8,000,000
Agreement [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Unused commitment fee on unused amount						1.75%
Agreement [Member] | Chubb Letter of Credit [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity				63,700,000		$ 63,700,000
Collateral transferred	$ 38,700,000
Agreement [Member] | Term Loan [Member]
Line of Credit Facility [Line Items]
Term loan from Bank, Interest rate description						one-month LIBOR plus 2.0%
Term loan with principal bank				$ 3,600,000		$ 3,600,000	$ 3,700,000
Payment of monthly principal of term loan						$ 18,375
Agreement [Member] | Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
LIBOR plus rate						2.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - Internal Revenue Service [Member] - USD ($)	1 Months Ended	6 Months Ended
	Jul. 31, 2020	Jun. 30, 2021
Income Tax Contingency [Line Items]
Open tax years		2011 2012 2013 2014
Wage based tax credits claimed amount to be disallowed results estimated additional tax due	$ 2,300,000
Wage-based tax credits claimed amount disallowed, tax years	2012 through 2015
Reserve for tax position	$ 0
Minimum [Member]
Income Tax Contingency [Line Items]
Ongoing audit for tax years	2011
Maximum [Member]
Income Tax Contingency [Line Items]
Ongoing audit for tax years	2014

Litigation - Additional Informa

Litigation - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)
Accrued Liabilities [Member]
Loss Contingencies [Line Items]
Estimated liability	$ 3.8
Kaanaana Case [Member]
Loss Contingencies [Line Items]
Actual Wages Paid	$ 2.2