Barrett Business Services (BBSI) 10-Q 4 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 21, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
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		7,646,324
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	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 61,193	$ 44,570
Investments	86,679	82,590
Trade accounts receivable, net	212,362	163,561
Income taxes receivable	1,740	1,335
Prepaid expenses and other	13,883	14,919
Restricted cash and investments	90,608	116,873
Total current assets	466,465	423,848
Property, equipment and software, net	35,148	31,724
Operating lease right-of-use assets	23,730	23,805
Restricted cash and investments	245,035	327,326
Goodwill	47,820	47,820
Other assets	5,081	3,618
Deferred income taxes		2,788
Total assets	823,279	860,929
Current liabilities:
Current portion of long-term debt	221	221
Accounts payable	6,447	5,993
Accrued payroll, payroll taxes and related benefits	205,476	174,168
Current operating lease liabilities	7,303	6,671
Other accrued liabilities	6,603	8,846
Workers' compensation claims liabilities	96,583	118,273
Safety incentives liability	23,354	27,950
Total current liabilities	345,987	342,122
Long-term workers' compensation claims liabilities	250,765	320,713
Long-term debt	3,565	3,730
Deferred income taxes	2,947
Long-term operating lease liabilities	17,355	17,883
Customer deposits and other long-term liabilities	5,348	4,682
Total liabilities	625,967	689,130
Commitments and contingencies (Notes 4 and 6)
Stockholders' equity:
Common stock, $.01 par value; 20,500 shares authorized, 7,646 and 7,514 shares issued and outstanding	76	75
Additional paid-in capital	23,938	20,227
Accumulated other comprehensive income	7,649	2,819
Retained earnings	165,649	148,678
Total stockholders' equity	197,312	171,799
Total liabilities and stockholders' equity	$ 823,279	$ 860,929

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
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	7,646,000	7,514,000
Common stock, shares outstanding	7,646,000	7,514,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Total revenues	$ 227,513	$ 247,962	$ 647,648	$ 697,159
Cost of revenues:
Total cost of revenues	168,279	177,198	515,720	542,929
Gross margin	59,234	70,764	131,928	154,230
Selling, general and administrative expenses	35,587	41,352	100,957	113,517
Depreciation and amortization	1,341	970	3,512	2,909
Income from operations	22,306	28,442	27,459	37,804
Other income (expense):
Investment income, net	1,664	2,882	6,431	9,286
Interest expense	(366)	(394)	(907)	(1,352)
Other, net	(4)		169	12
Other income, net	1,294	2,488	5,693	7,946
Income before income taxes	23,600	30,930	33,152	45,750
Provision for income taxes	5,089	5,959	6,538	9,172
Net income	$ 18,511	$ 24,971	$ 26,614	$ 36,578
Basic income per common share	$ 2,420	$ 3,340	$ 3,510	$ 4,920
Weighted average number of basic common shares outstanding	7,639	7,483	7,572	7,433
Diluted income per common share	$ 2,400	$ 3,240	$ 3,460	$ 4,760
Weighted average number of diluted common shares outstanding	7,709	7,711	7,688	7,686
Professional Employer Service Fees [Member]
Revenues:
Total revenues	$ 199,082	$ 214,156	$ 573,162	$ 607,840
Staffing Services [Member]
Revenues:
Total revenues	28,431	33,806	74,486	89,319
Direct Payroll Costs [Member]
Cost of revenues:
Total cost of revenues	21,452	25,464	56,325	67,298
Payroll Taxes and Benefits [Member]
Cost of revenues:
Total cost of revenues	100,142	104,847	313,275	321,341
Workers' Compensation [Member]
Cost of revenues:
Total cost of revenues	$ 46,685	$ 46,887	$ 146,120	$ 154,290

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 18,511	$ 24,971	$ 26,614	$ 36,578
Unrealized gains on investments, net of tax	688	987	4,830	7,687
Comprehensive income	$ 19,199	$ 25,958	$ 31,444	$ 44,265

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Unrealized gains on investments, tax	$ 263	$ 376	$ 1,847	$ 2,935

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 (Loss) Income [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2018	$ 119,037	$ 74	$ 15,437	$ (5,068)	$ 108,594
Beginning Balance, shares at Dec. 31, 2018		7,395
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	122		122
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		17
Common stock repurchased on vesting of restricted stock units and performance awards	(178)		(178)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(2)
Share-based compensation expense	1,387		1,387
Cash dividends on common stock	(1,852)				(1,852)
Unrealized gain (loss) on investments, net of tax	3,657			3,657
Net (loss) income	(2,300)				(2,300)
Ending Balance at Mar. 31, 2019	119,873	$ 74	16,768	(1,411)	104,442
Ending Balance, shares at Mar. 31, 2019		7,410
Beginning Balance at Dec. 31, 2018	119,037	$ 74	15,437	(5,068)	108,594
Beginning Balance, shares at Dec. 31, 2018		7,395
Unrealized gain (loss) on investments, net of tax	7,687
Net (loss) income	36,578
Ending Balance at Sep. 30, 2019	160,171	$ 75	18,259	2,619	139,218
Ending Balance, shares at Sep. 30, 2019		7,494
Beginning Balance at Mar. 31, 2019	119,873	$ 74	16,768	(1,411)	104,442
Beginning Balance, shares at Mar. 31, 2019		7,410
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	56		56
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		4
Share-based compensation expense	2,441		2,441
Cash dividends on common stock	(1,853)				(1,853)
Unrealized gain (loss) on investments, net of tax	3,043			3,043
Net (loss) income	13,907				13,907
Ending Balance at Jun. 30, 2019	137,467	$ 74	19,265	1,632	116,496
Ending Balance, shares at Jun. 30, 2019		7,414
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	280	$ 1	279
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		116
Common stock repurchased on vesting of restricted stock units and performance awards	(2,958)		(2,958)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(36)
Share-based compensation expense	1,673		1,673
Cash dividends on common stock	(2,249)				(2,249)
Unrealized gain (loss) on investments, net of tax	987			987
Net (loss) income	24,971				24,971
Ending Balance at Sep. 30, 2019	160,171	$ 75	18,259	2,619	139,218
Ending Balance, shares at Sep. 30, 2019		7,494
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	4,830
Net (loss) income	26,614
Ending Balance at Sep. 30, 2020	197,312	$ 76	23,938	7,649	165,649
Ending Balance, shares at Sep. 30, 2020		7,646
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
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards	300		300
Common stock issued on exercise of options, purchase of ESPP shares and vesting of restricted stock units and performance awards, shares		66
Common stock repurchased on vesting of restricted stock units and performance awards	(928)		(928)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(18)
Share-based compensation expense	1,145		1,145
Cash dividends on common stock	(2,292)				(2,292)
Unrealized gain (loss) on investments, net of tax	688			688
Net (loss) income	18,511				18,511
Ending Balance at Sep. 30, 2020	$ 197,312	$ 76	$ 23,938	$ 7,649	$ 165,649
Ending Balance, shares at Sep. 30, 2020		7,646

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Statement Of Stockholders Equity [Abstract]
Cash dividends on common stock per share	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.25	$ 0.25

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 26,614	$ 36,578
Reconciliations of net income to net cash (used in) provided by operating activities:
Depreciation and amortization	3,512	2,909
Non-cash lease expense	5,394	5,243
Investment (accretion) amortization and (gains) losses recognized	343	940
Deferred Income taxes	3,890
Share-based compensation	2,284	5,501
Changes in certain operating assets and liabilities:
Trade accounts receivable	(48,801)	(35,870)
Income taxes	(405)	(995)
Prepaid expenses and other	1,036	(2,094)
Accounts payable	454	1,096
Accrued payroll, payroll taxes and related benefits	32,554	40,763
Other accrued liabilities	(2,698)	(7,322)
Workers' compensation claims liabilities	(93,097)	16,857
Safety incentives liability	(4,596)	(1,483)
Operating lease liabilities	(5,215)	(4,673)
Other assets and liabilities, net	(130)	75
Net cash (used in) provided by operating activities	(78,861)	57,525
Cash flows from investing activities:
Purchase of property, equipment and software	(6,936)	(7,672)
Purchase of investments	(50,329)	(658)
Proceeds from sales and maturities of investments	46,791	15,941
Purchase of restricted investments	(32,508)	(3,946)
Proceeds from sales and maturities of restricted investments	45,160	42,409
Net cash provided by investing activities	2,178	46,074
Cash flows from financing activities:
Proceeds from credit-line borrowings		18,843
Payments on credit-line borrowings		(18,843)
Payments on long-term debt	(165)	(166)
Common stock repurchased on vesting of stock awards	(1,416)	(3,136)
Dividends paid	(6,826)	(5,954)
Proceeds from exercise of stock options	3,014	458
Net cash used in financing activities	(8,380)	(8,798)
Repurchase of common stock	(2,987)
Net (decrease) increase in cash, cash equivalents and restricted cash	(85,063)	94,801
Cash, cash equivalents and restricted cash, beginning of period	273,341	140,702
Cash, cash equivalents and restricted cash, end of period	$ 188,278	$ 235,503

Basis of Presentation of Interi

Basis of Presentation of Interim Period Statements	9 Months Ended
	Sep. 30, 2020
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 2019 Annual Report on Form 10-K at pages 32 – 58. 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 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 fronted insurance 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 $784,000 and $888,000 at September 30, 2020 and December 31, 2019, 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 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 nine months ended September 30, 2020 and 2019 did not materially differ from interest expense. Income taxes paid during the nine months ended September 30, 2020 totaled $3.2 million. Income taxes paid during the nine months ended September 30, 2019 totaled $10.1 million. 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): September 30, December 31, September 30, December 31, 2020 2019 2019 2018 Cash and cash equivalents $ 61,193 $ 44,570 $ 35,452 $ 35,371 Restricted cash, included in restricted cash and investments 127,085 228,771 200,051 105,331 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 188,278 $ 273,341 $ 235,503 $ 140,702 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 and the issuance of stock associated with outstanding restricted stock units. Basic and diluted shares outstanding are summarized as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Weighted average number of basic shares outstanding 7,639 7,483 7,572 7,433 Effect of dilutive securities 70 228 116 253 Weighted average number of diluted shares outstanding 7,709 7,711 7,688 7,686 Accounting estimates The preparation of our condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and 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. Recent accounting pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, “Financial Instruments – Credit Losses.” The ASU requires the use of an impairment model that is based on expected credit losses rather than incurred losses. The ASU also made changes to the impairment model for available-for-sale securities and requires the use of an allowance approach rather than writing down the security’s cost. The amendments in this update were adopted January 1, 2020 and did not have a material impact on the Company’s financial statements.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurement	Note 2 - Fair Value Measurement The following table summarizes the Company’s investments at September 30, 2020 and December 31, 2019 measured at fair value on a recurring basis (in thousands): September 30, 2020 December 31, 2019 Gross Gross Unrealized Unrealized Gains Recorded Gains Recorded Cost (Losses) Basis Cost (Losses) Basis Current: Cash equivalents: Money market funds $ 32,723 $ — $ 32,723 $ 35,526 $ — $ 35,526 Discount notes 9,998 1 9,999 — — — Total cash equivalents 42,721 1 42,722 35,526 — 35,526 Investments: Corporate bonds 36,732 558 37,290 53,493 156 53,649 Asset backed securities 36,950 (330 ) 36,620 14,017 (13 ) 14,004 U.S. government agency securities 7,399 791 8,190 7,408 282 7,690 Mortgage backed securities 4,465 13 4,478 2,737 1 2,738 U.S. treasuries 100 1 101 4,500 9 4,509 Total investments 85,646 1,033 86,679 82,155 435 82,590 Restricted cash and investments (1) Corporate bonds 95,881 4,461 100,342 98,481 1,931 100,412 Mortgage backed securities 52,650 2,481 55,131 62,930 837 63,767 Money market funds 32,879 3 32,882 29,046 — 29,046 U.S. government agency securities 25,697 2,514 28,211 27,885 642 28,527 Commercial paper 5,998 1 5,999 — — — Supranational bonds 4,773 29 4,802 4,770 30 4,800 U.S. treasuries 4,760 31 4,791 16,906 21 16,927 Mutual funds 4,712 — 4,712 3,466 — 3,466 Municipal bonds 4,062 14 4,076 — — — Asset backed securities 270 5 275 303 — 303 Total restricted cash and investments 231,682 9,539 241,221 243,787 3,461 247,248 Total investments $ 360,049 $ 10,573 $ 370,622 $ 361,468 $ 3,896 $ 365,364 (1) Included in restricted cash and investments within the condensed consolidated balance sheets is restricted cash of $94.4 million and $197.0 million as of September 30, 2020 and December 31, 2019, respectively, which is excluded from the table above. Restricted cash and investments are classified as current and noncurrent on the balance sheets based on the nature of the restriction. The following table summarizes the Company’s investments at September 30, 2020 and December 31, 2019 measured at fair value on a recurring basis by fair value hierarchy level (in thousands): September 30, 2020 December 31, 2019 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 $ 32,723 $ — $ — $ — $ 32,723 $ 35,526 $ — $ — $ — $ 35,526 Discount notes 9,999 — 9,999 — — — — — — — Investments: Corporate bonds 37,290 — 37,290 — — 53,649 — 53,649 — — Asset backed securities 36,620 — 36,620 — — 14,004 — 14,004 — — U.S. government agency securities 8,190 — 8,190 — — 7,690 — 7,690 — — Mortgage backed securities 4,478 — 4,478 — — 2,738 — 2,738 — — U.S. treasuries 101 — 101 — — 4,509 — 4,509 — — Restricted cash and investments: — Corporate bonds 100,342 — 100,342 — — 100,412 — 100,412 — — Mortgage backed securities 55,131 — 55,131 — — 63,767 — 63,767 — — Money market funds 32,882 — — — 32,882 29,046 — — — 29,046 U.S. government agency securities 28,211 — 28,211 — — 28,527 — 28,527 — — Commercial paper 5,999 — 5,999 — — — — — — — Supranational bonds 4,802 — 4,802 — — 4,800 — 4,800 — — U.S. treasuries 4,791 — 4,791 — — 16,927 — 16,927 — — Mutual funds 4,712 4,712 — — — 3,466 3,466 — — — Municipal bonds 4,076 — 4,076 — — — — — — Asset backed securities 275 — 275 — — 303 — 303 — — Total investments $ 370,622 $ 4,712 $ 300,305 $ — $ 65,605 $ 365,364 $ 3,466 $ 297,326 $ — $ 64,572 (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 September 30, 2020. Actual maturities may differ from contractual maturities because borrowers may have the right to prepay obligations with or without prepayment penalties. September 30, 2020 (In thousands) Less than 1 Year Between 1 to 5 Years Between 5 to 10 Years After 10 Years Total Corporate bonds $ 41,077 $ 62,479 $ 34,076 $ — $ 137,632 Money market funds 65,605 — — — 65,605 Asset backed securities — 286 — 36,609 36,895 U.S. government agency securities 1,018 14,646 20,737 — 36,401 Discount notes 9,999 — — — 9,999 Commercial paper 5,999 — — — 5,999 U.S. treasuries 3,330 1,562 — — 4,892 Supranational bonds 4,802 — — — 4,802 Municipal bonds — 4,076 — — 4,076 Total $ 131,830 $ 83,049 $ 54,813 $ 36,609 $ 306,301 The average contractual maturity of mortgage backed securities, which are excluded from the table above, was 18 years as of September 30, 2020.

Workers' Compensation Claims

Workers' Compensation Claims	9 Months Ended
	Sep. 30, 2020
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 Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Beginning balance Workers' compensation claims liabilities $ 336,504 $ 430,736 $ 438,986 $ 413,397 Add: claims expense accrual Current period 35,138 37,404 106,359 118,934 Prior periods (2,977 ) (5,593 ) (5,163 ) (10,245 ) 32,161 31,811 101,196 108,689 Less: claim payments related to Current period 7,046 8,609 13,123 14,213 Prior periods 15,640 23,815 181,170 77,619 22,686 32,424 194,293 91,832 Change in claims incurred in excess of retention limits 1,369 (77 ) 1,459 (208 ) Ending balance Workers' compensation claims liabilities $ 347,348 $ 430,046 $ 347,348 $ 430,046 Incurred but not reported (IBNR) $ 203,595 $ 274,344 $ 203,595 $ 274,344 Ratio of IBNR to workers' compensation claims liabilities 59 % 64 % 59 % 64 % The Company is a self-insured employer with respect to workers' compensation coverage for all of its employees (including employees co-employed through our client service agreements) 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 progra m. The Company also operates a wholly owned, fully licensed insurance company, Ecole, which provides workers’ compensation coverage to the Company’s employees working in Arizona and Utah. For all other clients, the Company obtains policies from Chubb Limited (“Chubb”) through an arrangement known as a fronted program, which provides a licensed, admitted insurance carrier to issue policies on behalf of the Company. Chubb assumes credit risk should the Company be unable to satisfy its indemnification obligations. Through various insurance arrangements, the Company retains risk of loss up to the first $3.0 million per occurrence, except in Maryland and Colorado, where our retention per occurrence is $1.0 million and $2.0 million, respectively. The fronted program with Chubb requires that collateral be advanced at the inception of the policy term. To partially satisfy these collateral requirements, the Company provided a letter of credit of $63.7 million from its principal bank, Wells Fargo Bank, National Association (the “Bank”). In addition, The states of California, Maryland, Oregon, Washington, Colorado and Delaware required us to maintain collateral totaling $59.7 million and $76.1 million at September 30, 2020 and December 31, 2019, respectively, to cover potential workers’ compensation claims losses related to the Company’s current and former status as a self-insured employer. At September 30, 2020, the Company provided surety bonds and standby letters of credit totaling $59.7 million, including a California requirement of $39.2 million. On June 29, 2020, the Company entered into a loss portfolio transfer agreement to remove all outstanding workers’ compensation claims obligations for claims incurred under its fronted insurance program between February 1, 2014 and December 31, 2017. This transaction reduced the Company’s outstanding workers’ compensation liabilities and Chubb trust account balances by $115.7 million. As of September 30, 2020, the Company recorded a receivable from Chubb of $0.7 million related to claim payments made on Chubb’s behalf for claim obligations transferred to Chubb as part of the loss portfolio transfer agreement. The amount is included in prepaid expenses and other on the condensed consolidated balance sheets. The Company provided a total of $347.3 million and $439.0 million at September 30, 2020 and December 31, 2019, respectively, as an estimated future liability for unsettled workers' compensation claims liabilities. Of this amount, $4.8 million and $3.3 million at September 30, 2020 and December 31, 2019, 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 excess insurance carriers of $4.8 million and $3.3 million at September 30, 2020 and December 31, 2019, respectively, included on other assets on the condensed consolidated balance sheets.

Revolving Credit Facility and L

Revolving Credit Facility and Long-Term Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Revolving Credit Facility and Long-Term Debt	Note 4 - Revolving Credit Facility and Long-Term Debt On September 30, 2020, the Company entered into an amended credit agreement (the “Agreement”) with the Bank, which reverted to the provisions set forth in the agreement prior to May 15, 2020. The Agreement reduced the revolving credit line from $50.0 million back to $33.0 million; the sublimit for standby letters of credit remains at $8.0 million. At September 30, 2020, $5.8 million of the sublimit for standby letters of credit was used. The Agreement expires on July 1, 2022. 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 Agreement also provides for a $63.7 million standby letter of credit (the “Chubb Letter of Credit”). The Chubb Letter of Credit has an expiration date of July 1, 2021, subject to automatic renewal in specified circumstances. The Bank has been granted a security interest of first priority in certain blocked securities accounts (collectively, the “Collateral Accounts”). The Company has agreed to deposit in the Collateral Accounts 50% of the Company’s consolidated net income (after tax and less cash dividends) for each quarter plus, to the extent necessary, an additional amount by May 15 each year so that the deposits in the Collateral Accounts for the prior year total at least $16 million. Through the third quarter of 2020, the Company deposited $32.5 million into the Collateral Accounts. The initial fee paid under the Chubb Letter of Credit in June 2018 was equal to 2.5% of the face amount thereof. Upon annual renewal, the fees payable to the Bank quarterly in advance include (a) a fee at the annual rate of 2.5%, calculated based on the difference between the face amount of the Chubb Letter of Credit and 95% of the aggregate value of the Collateral Accounts as of the end of the previous quarter, (b) a fee at the annual rate of 1.0% calculated based on the balance of the face amount, and (c) other fees upon the payment or negotiation of each drawing under the Chubb Letter of Credit. 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 September 30, 2020, the Company was in compliance with all covenants. The Company maintains a mortgage loan with the Bank with a balance of approximately $3.8 million and $4.0 million at September 30, 2020 and December 31, 2019, 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	9 Months Ended
	Sep. 30, 2020
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 September 30, 2020. 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 a draft Revenue Agent Report in relation to the ongoing IRS audit for tax years 2011 to 2014. The report indicates that the IRS intends to disallow certain wage-based tax credits claimed, which would result in an estimated total additional tax due of approximately $2.3 million for the tax years 2012 through 2014. The Company strongly disagrees with the asserted grounds for this determination and plans to pursue all available administrative and judicial remedies necessary to vigorously defend its position. Based on management’s analysis of this matter, no reserve has been recorded in the financial statements. In the major jurisdictions where it operates, the Company is generally no longer subject to income tax examinations by tax authorities for the 2015 tax year and tax years before 2011. As of September 30, 2020, 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	9 Months Ended
	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Litigation	Note 6 – Litigation On November 21, 2012, David Kaanaana (“Kaanaana”), a former staffing employee, filed a California wage and hour violations lawsuit against BBSI. On May 19, 2016, the court entered a ruling in favor of BBSI, which was subsequently appealed by the plaintiffs. 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 plaintiffs' claims and holding that prevailing wage requirements applicable to “public works” apply to certain types of districts. On January 9, 2019, BBSI filed a petition of review to the California Supreme Court. An amicus letter in support of the petition was filed by the Sanitation Districts of Los Angeles County, joined in by numerous other "special districts" in California. On February 27, 2019, the California Supreme Court granted the petition to review the appellate court’s decision, and a hearing date remains pending. BBSI is subject to other legal proceedings and claims that arise in the ordinary course of our business.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Note 7 – Subsequent Events In October 2020, prior to the close of our trading window, the Company reinstated its stock repurchase plan and repurchased 57,018 shares at an average price of $53.61 per share.

Basis of Presentation of Inte_2

Basis of Presentation of Interim Period Statements (Policies)	9 Months Ended
	Sep. 30, 2020
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 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 fronted insurance 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 $784,000 and $888,000 at September 30, 2020 and December 31, 2019, 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 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 nine months ended September 30, 2020 and 2019 did not materially differ from interest expense. Income taxes paid during the nine months ended September 30, 2020 totaled $3.2 million. Income taxes paid during the nine months ended September 30, 2019 totaled $10.1 million. 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): September 30, December 31, September 30, December 31, 2020 2019 2019 2018 Cash and cash equivalents $ 61,193 $ 44,570 $ 35,452 $ 35,371 Restricted cash, included in restricted cash and investments 127,085 228,771 200,051 105,331 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 188,278 $ 273,341 $ 235,503 $ 140,702
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 and the issuance of stock associated with outstanding restricted stock units. Basic and diluted shares outstanding are summarized as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Weighted average number of basic shares outstanding 7,639 7,483 7,572 7,433 Effect of dilutive securities 70 228 116 253 Weighted average number of diluted shares outstanding 7,709 7,711 7,688 7,686
Accounting estimates	Accounting estimates The preparation of our condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and 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.
Recent accounting pronouncements	Recent accounting pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, “Financial Instruments – Credit Losses.” The ASU requires the use of an impairment model that is based on expected credit losses rather than incurred losses. The ASU also made changes to the impairment model for available-for-sale securities and requires the use of an allowance approach rather than writing down the security’s cost. The amendments in this update were adopted January 1, 2020 and did not have a material impact on the Company’s financial statements.

Basis of Presentation of Inte_3

Basis of Presentation of Interim Period Statements (Tables)	9 Months Ended
	Sep. 30, 2020
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): September 30, December 31, September 30, December 31, 2020 2019 2019 2018 Cash and cash equivalents $ 61,193 $ 44,570 $ 35,452 $ 35,371 Restricted cash, included in restricted cash and investments 127,085 228,771 200,051 105,331 Total cash, cash equivalents and restricted cash shown in the statement of cash flows $ 188,278 $ 273,341 $ 235,503 $ 140,702
Summary of Basic and Diluted Common Shares Outstanding	Basic and diluted shares outstanding are summarized as follows (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Weighted average number of basic shares outstanding 7,639 7,483 7,572 7,433 Effect of dilutive securities 70 228 116 253 Weighted average number of diluted shares outstanding 7,709 7,711 7,688 7,686

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Summary of Investments Measured at Fair Value on Recurring Basis	The following table summarizes the Company’s investments at September 30, 2020 and December 31, 2019 measured at fair value on a recurring basis (in thousands): September 30, 2020 December 31, 2019 Gross Gross Unrealized Unrealized Gains Recorded Gains Recorded Cost (Losses) Basis Cost (Losses) Basis Current: Cash equivalents: Money market funds $ 32,723 $ — $ 32,723 $ 35,526 $ — $ 35,526 Discount notes 9,998 1 9,999 — — — Total cash equivalents 42,721 1 42,722 35,526 — 35,526 Investments: Corporate bonds 36,732 558 37,290 53,493 156 53,649 Asset backed securities 36,950 (330 ) 36,620 14,017 (13 ) 14,004 U.S. government agency securities 7,399 791 8,190 7,408 282 7,690 Mortgage backed securities 4,465 13 4,478 2,737 1 2,738 U.S. treasuries 100 1 101 4,500 9 4,509 Total investments 85,646 1,033 86,679 82,155 435 82,590 Restricted cash and investments (1) Corporate bonds 95,881 4,461 100,342 98,481 1,931 100,412 Mortgage backed securities 52,650 2,481 55,131 62,930 837 63,767 Money market funds 32,879 3 32,882 29,046 — 29,046 U.S. government agency securities 25,697 2,514 28,211 27,885 642 28,527 Commercial paper 5,998 1 5,999 — — — Supranational bonds 4,773 29 4,802 4,770 30 4,800 U.S. treasuries 4,760 31 4,791 16,906 21 16,927 Mutual funds 4,712 — 4,712 3,466 — 3,466 Municipal bonds 4,062 14 4,076 — — — Asset backed securities 270 5 275 303 — 303 Total restricted cash and investments 231,682 9,539 241,221 243,787 3,461 247,248 Total investments $ 360,049 $ 10,573 $ 370,622 $ 361,468 $ 3,896 $ 365,364 (1) Included in restricted cash and investments within the condensed consolidated balance sheets is restricted cash of $94.4 million and $197.0 million as of September 30, 2020 and December 31, 2019, respectively, which is excluded from the table above. Restricted cash and investments are classified as current and noncurrent on the balance sheets 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 September 30, 2020 and December 31, 2019 measured at fair value on a recurring basis by fair value hierarchy level (in thousands): September 30, 2020 December 31, 2019 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 $ 32,723 $ — $ — $ — $ 32,723 $ 35,526 $ — $ — $ — $ 35,526 Discount notes 9,999 — 9,999 — — — — — — — Investments: Corporate bonds 37,290 — 37,290 — — 53,649 — 53,649 — — Asset backed securities 36,620 — 36,620 — — 14,004 — 14,004 — — U.S. government agency securities 8,190 — 8,190 — — 7,690 — 7,690 — — Mortgage backed securities 4,478 — 4,478 — — 2,738 — 2,738 — — U.S. treasuries 101 — 101 — — 4,509 — 4,509 — — Restricted cash and investments: — Corporate bonds 100,342 — 100,342 — — 100,412 — 100,412 — — Mortgage backed securities 55,131 — 55,131 — — 63,767 — 63,767 — — Money market funds 32,882 — — — 32,882 29,046 — — — 29,046 U.S. government agency securities 28,211 — 28,211 — — 28,527 — 28,527 — — Commercial paper 5,999 — 5,999 — — — — — — — Supranational bonds 4,802 — 4,802 — — 4,800 — 4,800 — — U.S. treasuries 4,791 — 4,791 — — 16,927 — 16,927 — — Mutual funds 4,712 4,712 — — — 3,466 3,466 — — — Municipal bonds 4,076 — 4,076 — — — — — — Asset backed securities 275 — 275 — — 303 — 303 — — Total investments $ 370,622 $ 4,712 $ 300,305 $ — $ 65,605 $ 365,364 $ 3,466 $ 297,326 $ — $ 64,572 (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 September 30, 2020. Actual maturities may differ from contractual maturities because borrowers may have the right to prepay obligations with or without prepayment penalties. September 30, 2020 (In thousands) Less than 1 Year Between 1 to 5 Years Between 5 to 10 Years After 10 Years Total Corporate bonds $ 41,077 $ 62,479 $ 34,076 $ — $ 137,632 Money market funds 65,605 — — — 65,605 Asset backed securities — 286 — 36,609 36,895 U.S. government agency securities 1,018 14,646 20,737 — 36,401 Discount notes 9,999 — — — 9,999 Commercial paper 5,999 — — — 5,999 U.S. treasuries 3,330 1,562 — — 4,892 Supranational bonds 4,802 — — — 4,802 Municipal bonds — 4,076 — — 4,076 Total $ 131,830 $ 83,049 $ 54,813 $ 36,609 $ 306,301

Workers' Compensation Claims (T

Workers' Compensation Claims (Tables)	9 Months Ended
	Sep. 30, 2020
Text Block [Abstract]
Summarizes Aggregate Workers' Compensation Reserve Activity	The following table summarizes the aggregate workers’ compensation reserve activity (in thousands): Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Beginning balance Workers' compensation claims liabilities $ 336,504 $ 430,736 $ 438,986 $ 413,397 Add: claims expense accrual Current period 35,138 37,404 106,359 118,934 Prior periods (2,977 ) (5,593 ) (5,163 ) (10,245 ) 32,161 31,811 101,196 108,689 Less: claim payments related to Current period 7,046 8,609 13,123 14,213 Prior periods 15,640 23,815 181,170 77,619 22,686 32,424 194,293 91,832 Change in claims incurred in excess of retention limits 1,369 (77 ) 1,459 (208 ) Ending balance Workers' compensation claims liabilities $ 347,348 $ 430,046 $ 347,348 $ 430,046 Incurred but not reported (IBNR) $ 203,595 $ 274,344 $ 203,595 $ 274,344 Ratio of IBNR to workers' compensation claims liabilities 59 % 64 % 59 % 64 %

Basis of Presentation of Inte_4

Basis of Presentation of Interim Period Statements - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2020USD ($)Company	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
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	$ 784,000		$ 888,000
Estimate of liability for unpaid safety incentives	23,400,000		$ 28,000,000
Income taxes paid	$ 3,200,000	$ 10,100,000

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	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 61,193	$ 44,570	$ 35,452	$ 35,371
Restricted cash, included in restricted cash and investments	127,085	228,771	200,051	105,331
Total cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 188,278	$ 273,341	$ 235,503	$ 140,702

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		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Weighted Average Number Of Shares Outstanding Diluted Disclosure Items [Abstract]
Weighted average number of basic shares outstanding	7,639	7,483	7,572	7,433
Effect of dilutive securities	70	228	116	253
Weighted average number of diluted shares outstanding	7,709	7,711	7,688	7,686

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	$ 360,049	$ 361,468
Gross Unrealized Gains (Losses)	10,573	3,896
Recorded Basis	370,622	365,364
Cash and Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	42,721	35,526
Gross Unrealized Gains (Losses)	1
Recorded Basis	42,722	35,526
Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	32,723	35,526
Recorded Basis	32,723	35,526
Cash and Cash Equivalents [Member] | Discount Notes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	9,998
Gross Unrealized Gains (Losses)	1
Recorded Basis	9,999
Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	85,646	82,155
Gross Unrealized Gains (Losses)	1,033	435
Recorded Basis	86,679	82,590
Investments [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	36,732	53,493
Gross Unrealized Gains (Losses)	558	156
Recorded Basis	37,290	53,649
Investments [Member] | Asset Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	36,950	14,017
Gross Unrealized Gains (Losses)	(330)	(13)
Recorded Basis	36,620	14,004
Investments [Member] | U.S. Government Agency Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	7,399	7,408
Gross Unrealized Gains (Losses)	791	282
Recorded Basis	8,190	7,690
Investments [Member] | U.S. Treasuries [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	100	4,500
Gross Unrealized Gains (Losses)	1	9
Recorded Basis	101	4,509
Investments [Member] | Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	4,465	2,737
Gross Unrealized Gains (Losses)	13	1
Recorded Basis	4,478	2,738
Restricted Cash and Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	231,682	243,787
Gross Unrealized Gains (Losses)	9,539	3,461
Recorded Basis	241,221	247,248
Restricted Cash and Investments [Member] | Money Market Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	32,879	29,046
Gross Unrealized Gains (Losses)	3
Recorded Basis	32,882	29,046
Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	95,881	98,481
Gross Unrealized Gains (Losses)	4,461	1,931
Recorded Basis	100,342	100,412
Restricted Cash and Investments [Member] | Asset Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	270	303
Gross Unrealized Gains (Losses)	5
Recorded Basis	275	303
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	25,697	27,885
Gross Unrealized Gains (Losses)	2,514	642
Recorded Basis	28,211	28,527
Restricted Cash and Investments [Member] | U.S. Treasuries [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	4,760	16,906
Gross Unrealized Gains (Losses)	31	21
Recorded Basis	4,791	16,927
Restricted Cash and Investments [Member] | Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	52,650	62,930
Gross Unrealized Gains (Losses)	2,481	837
Recorded Basis	55,131	63,767
Restricted Cash and Investments [Member] | Commercial Paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	5,998
Gross Unrealized Gains (Losses)	1
Recorded Basis	5,999
Restricted Cash and Investments [Member] | Municipal Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	4,062
Gross Unrealized Gains (Losses)	14
Recorded Basis	4,076
Restricted Cash and Investments [Member] | Supranational Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	4,773	4,770
Gross Unrealized Gains (Losses)	29	30
Recorded Basis	4,802	4,800
Restricted Cash and Investments [Member] | Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost	4,712	3,466
Recorded Basis	$ 4,712	$ 3,466

Fair Value Measurement - Summ_2

Fair Value Measurement - Summary of Investments Measured at Fair Value on Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Restricted cash	$ 94.4	$ 197

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	Sep. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	$ 370,622	$ 365,364
Other [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	65,605	64,572
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	4,712	3,466
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	300,305	297,326
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	32,723	35,526
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	32,723	35,526
Cash and Cash Equivalents [Member] | Discount Notes [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	9,999
Cash and Cash Equivalents [Member] | Discount Notes [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	9,999
Investments [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	37,290	53,649
Investments [Member] | Corporate Bonds [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	37,290	53,649
Investments [Member] | Mortgage Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	4,478	2,738
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	4,478	2,738
Investments [Member] | U.S. Treasuries [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	101	4,509
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	101	4,509
Investments [Member] | U.S. Government Agency Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	8,190	7,690
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	8,190	7,690
Investments [Member] | Asset Backed Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	36,620	14,004
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	36,620	14,004
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	32,882	29,046
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	32,882	29,046
Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	100,342	100,412
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	100,342	100,412
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	55,131	63,767
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	55,131	63,767
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	4,791	16,927
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	4,791	16,927
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	28,211	28,527
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	28,211	28,527
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	275	303
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	275	303
Restricted Cash and Investments [Member] | Commercial Paper [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	5,999
Restricted Cash and Investments [Member] | Commercial Paper [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	5,999
Restricted Cash and Investments [Member] | Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	4,712	3,466
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	4,712	3,466
Restricted Cash and Investments [Member] | Supranational Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	4,802	4,800
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	4,802	$ 4,800
Restricted Cash and Investments [Member] | Municipal Bonds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	4,076
Restricted Cash and Investments [Member] | Municipal Bonds [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total Recorded Basis	$ 4,076

Fair Value Measurement - Summ_4

Fair Value Measurement - Summary of Contractual Maturities of Available for Sale Securities (Detail) $ in Thousands	Sep. 30, 2020USD ($)
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	$ 131,830
Available for sale securities, contractual maturities between 1 to 5 years	83,049
Available for sale securities, contractual maturities between 5 to 10 years	54,813
Available for sale securities, contractual maturities after 10 years	36,609
Available for sale securities, contractual maturities, Total	306,301
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	41,077
Available for sale securities, contractual maturities between 1 to 5 years	62,479
Available for sale securities, contractual maturities between 5 to 10 years	34,076
Available for sale securities, contractual maturities, Total	137,632
Money Market Funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	65,605
Available for sale securities, contractual maturities, Total	65,605
U.S. Government Agency Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	1,018
Available for sale securities, contractual maturities between 1 to 5 years	14,646
Available for sale securities, contractual maturities between 5 to 10 years	20,737
Available for sale securities, contractual maturities, Total	36,401
Asset Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities between 1 to 5 years	286
Available for sale securities, contractual maturities after 10 years	36,609
Available for sale securities, contractual maturities, Total	36,895
Discount Notes [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	9,999
Available for sale securities, contractual maturities, Total	9,999
Commercial Paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	5,999
Available for sale securities, contractual maturities, Total	5,999
U.S. Treasuries [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	3,330
Available for sale securities, contractual maturities between 1 to 5 years	1,562
Available for sale securities, contractual maturities, Total	4,892
Supranational Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	4,802
Available for sale securities, contractual maturities, Total	4,802
Municipal Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities between 1 to 5 years	4,076
Available for sale securities, contractual maturities, Total	$ 4,076

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2020
Mortgage Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Average contractual maturity period	18 years

Workers' Compensation Claims -

Workers' Compensation Claims - Summarizes Aggregate Workers' Compensation Reserve Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Workers Compensation Reserve [Abstract]
Workers' compensation claims liabilities, Beginning balance	$ 336,504	$ 430,736	$ 438,986	$ 413,397
Add: claims expense accrual
Current period	35,138	37,404	106,359	118,934
Prior periods	(2,977)	(5,593)	(5,163)	(10,245)
Total expense accrual	32,161	31,811	101,196	108,689
Less: claim payments related to
Current period	7,046	8,609	13,123	14,213
Prior periods	15,640	23,815	181,170	77,619
Total paid	22,686	32,424	194,293	91,832
Change in claims incurred in excess of retention limits	1,369	(77)	1,459	(208)
Workers' compensation claims liabilities, Ending balance	347,348	430,046	347,348	430,046
Incurred but not reported (IBNR)	$ 203,595	$ 274,344	$ 203,595	$ 274,344
Ratio of IBNR to workers' compensation claims liabilities	59.00%	64.00%	59.00%	64.00%

Workers' Compensation Claims _2

Workers' Compensation Claims - Additional Information (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Jun. 30, 2020	Jun. 29, 2020	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Worker's compensation risk claim maximum	$ 3,000,000
Balance in Chubb trust accounts	277,400,000	$ 393,500,000		$ 115,700,000
Collateral securities maintain to cover potential workers compensation claims losses	59,700,000	76,100,000
Surety bonds and standby letters of credit	59,700,000
Claim payments receivable from Chubb			$ 700,000
Estimated future liability for unsettled workers' compensation	347,348,000	438,986,000	$ 336,504,000		$ 430,046,000	$ 430,736,000	$ 413,397,000
Reserves incurred in excess of retention limits	4,800,000	3,300,000
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	4,800,000	$ 3,300,000
Wells Fargo Bank, National Association [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Letter of credit	63,700,000
Maryland [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reinsurance coverage	1,000,000
Colorado [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Reinsurance coverage	2,000,000
California [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Surety bonds and standby letters of credit	$ 39,200,000

Revolving Credit Facility and_2

Revolving Credit Facility and Long-Term Debt - Additional Information (Detail) - Agreement [Member] - USD ($)	1 Months Ended	3 Months Ended				9 Months Ended
	Jun. 30, 2018	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2020	May 14, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Credit facility borrowing used			$ 5,800,000			$ 5,800,000
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
Ratio of restricted and unrestricted cash and investments to workers' compensation and claim liabilities			1.00%	1.00%	1.00%
Dividends or distributions paid						0
Maximum amount to redeem retire repurchase or acquire stock upon agreement						15,000,000
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%
Minimum [Member]
Line of Credit Facility [Line Items]
EBITDA			$ 30,000,000	$ 30,000,000	$ 30,000,000	30,000,000
Minimum [Member] | Scenario Forecast [Member]
Line of Credit Facility [Line Items]
EBITDA		$ 30,000,000
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
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity			33,000,000			$ 33,000,000	$ 50,000,000
Credit facility, expiration date						Jul. 1, 2022
Unused commitment fee on unused amount during period						0.375%
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%
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%
Standby Letters of Credit [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity			8,000,000			$ 8,000,000
Line of Credit [Member]
Line of Credit Facility [Line Items]
Unused commitment fee on unused amount						1.75%
Chubb Letter of Credit [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity			$ 63,700,000			$ 63,700,000
Credit facility, expiration date						Jul. 1, 2021
Percentage of initial fee under letter of credit	2.50%					2.50%
Percentage of aggregate fee under letter of credit						95.00%
Percentage of annual fee under letter of credit			1.00%			1.00%
Chubb Letter of Credit [Member] | Collateral Accounts [Member]
Line of Credit Facility [Line Items]
Percentage of deposit in collateral accounts						50.00%
Deposit in collateral accounts			$ 32,500,000			$ 32,500,000
Chubb Letter of Credit [Member] | Collateral Accounts [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Deposit in collateral accounts			16,000,000			$ 16,000,000
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			$ 3,800,000			$ 3,800,000		$ 4,000,000
Payment of monthly principal of term loan						$ 18,375
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	9 Months Ended
	Jul. 31, 2020	Sep. 30, 2020
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 2014
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

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent Event [Member]	Oct. 31, 2020$ / sharesshares
Subsequent Event [Line Items]
Stock repurchased under repurchase plan | shares	57,018
Stock repurchase plan average price | $ / shares	$ 53.61