Barrett Business Services (BBSI) 10-Q 9 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Nov. 01, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Trading Symbol	BBSI
Entity Registrant Name	BARRETT BUSINESS SERVICES INC
Entity Central Index Key	902,791
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		7,243,667

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 26,786	$ 25,218
Trade accounts receivable, net	140,074	90,529
Income taxes receivable	0	1,038
Prepaid expenses and other	3,637	3,173
Investments	1,013	0
Restricted cash and investments	51,959	86,110
Deferred income taxes	20,906	20,941
Total current assets	244,375	227,009
Investments	863	6,082
Property, equipment and software, net	25,790	22,820
Restricted cash and investments	245,020	187,916
Goodwill	47,820	47,820
Other assets	15,937	5,130
Total assets	579,805	496,777
Current liabilities:
Current portion of long-term debt	221	19,833
Accounts payable	4,520	3,217
Accrued payroll, payroll taxes and related benefits	161,062	121,343
Income taxes payable	4,797	0
Other accrued liabilities	10,751	6,166
Workers' compensation claims liabilities	77,683	65,581
Safety incentives liability	24,997	21,253
Total current liabilities	284,031	237,393
Long-term workers' compensation claims liabilities	214,248	190,094
Long-term debt	4,447	0
Deferred income taxes	13,256	13,256
Customer deposits and other long-term liabilities	1,443	1,483
Total liabilities	517,425	442,226
Commitments and contingencies (Notes 4 and 6)
Stockholders' equity:
Common stock, $.01 par value; 20,500 shares authorized, 7,244 and 7,203 shares issued and outstanding	72	72
Additional paid-in capital	8,749	6,964
Accumulated other comprehensive income (loss)	27	(31)
Retained earnings	53,532	47,546
Total stockholders' equity	62,380	54,551
Total liabilities and stockholders' equity	$ 579,805	$ 496,777

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2016	Dec. 31, 2015
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	7,244,000	7,203,000
Common stock, shares outstanding	7,244,000	7,203,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues:
Professional employer service fees	$ 177,229	$ 152,108	$ 497,682	$ 418,954
Staffing services	47,874	46,617	121,806	128,130
Total revenues	225,103	198,725	619,488	547,084
Cost of revenues:
Direct payroll costs	37,017	35,308	92,667	97,260
Payroll taxes and benefits	82,888	75,237	269,533	235,122
Workers' compensation	55,639	45,290	155,089	126,403
Total cost of revenues	175,544	155,835	517,289	458,785
Gross margin	49,559	42,890	102,199	88,299
Selling, general and administrative expenses	30,440	25,440	80,834	63,839
Depreciation and amortization	823	721	2,341	2,113
Income from operations	18,296	16,729	19,024	22,347
Other income (expense):
Investment income	194	254	702	570
Interest expense	(196)	(467)	(704)	(1,549)
Loss on litigation	(3,305)	0	(3,305)	0
Other, net	27	(3)	26	(82)
Other expense, net	(3,280)	(216)	(3,281)	(1,061)
Income before income taxes	15,016	16,513	15,743	21,286
Provision for income taxes	4,783	5,540	4,991	7,239
Net income	$ 10,233	$ 10,973	$ 10,752	$ 14,047
Basic earnings per common share	$ 1.41	$ 1.52	$ 1.49	$ 1.96
Weighted average number of basic common shares outstanding	7,243	7,201	7,220	7,163
Diluted earnings per common share	$ 1.38	$ 1.49	$ 1.46	$ 1.91
Weighted average number of diluted common shares outstanding	7,405	7,362	7,350	7,340
Cash dividends per common share	$ 0.22	$ 0.22	$ 0.66	$ 0.66

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 10,233	$ 10,973	$ 10,752	$ 14,047
Unrealized gains on investments, net of tax	4	6	58	33
Comprehensive income	$ 10,237	$ 10,979	$ 10,810	$ 14,080

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Unrealized gains on investments, tax	$ 2	$ 4	$ 35	$ 21

Condensed Consolidated Stateme7

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, 2014	[1]	$ 32,820	$ 71	$ 4,410	$ (23)	$ 28,362
Beginning balance, shares at Dec. 31, 2014	[1]		7,126
Common stock issued on exercise of options and vesting of restricted stock units		689	$ 1	688	0	0
Common stock issued on exercise of options and vesting of restricted stock units, shares			88
Common stock repurchased on vesting of restricted stock units		(465)	$ 0	(465)	0	0
Common stock repurchased on vesting of restricted stock units, shares			(12)
Share based compensation expense		1,727	$ 0	1,727	0	0
Excess tax benefits from share-based compensation		56	0	56	0	0
Cash dividends on common stock		(4,726)	0	0	0	(4,726)
Unrealized gain on investments, net of tax		33	0	0	33	0
Net income		14,047	0	0	0	14,047
Ending balance at Sep. 30, 2015	[1]	44,181	$ 72	6,416	10	37,683
Ending balance, shares at Sep. 30, 2015	[1]		7,202
Beginning balance at Dec. 31, 2015		54,551	$ 72	6,964	(31)	47,546
Beginning balance, shares at Dec. 31, 2015			7,203
Common stock issued on exercise of options and vesting of restricted stock units		72	$ 0	72	0	0
Common stock issued on exercise of options and vesting of restricted stock units, shares			52
Common stock repurchased on vesting of restricted stock units		(433)	$ 0	(433)	0	0
Common stock repurchased on vesting of restricted stock units, shares			(11)
Share based compensation expense		1,881	$ 0	1,881	0	0
Excess tax benefits from share-based compensation		265	0	265	0	0
Cash dividends on common stock		(4,766)	0	0	0	(4,766)
Unrealized gain on investments, net of tax		58	0	0	58	0
Net income		10,752	0	0	0	10,752
Ending balance at Sep. 30, 2016		$ 62,380	$ 72	$ 8,749	$ 27	$ 53,532
Ending balance, shares at Sep. 30, 2016			7,244
[1]	See restatement disclosure in 2015 Form 10-K

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 10,752	$ 14,047
Reconciliations of net income to net cash provided by operating activities:
Depreciation and amortization	2,341	2,113
Losses (gains) recognized on investments	3	(2)
Losses recognized on sale of property and equipment	31	0
Deferred income taxes	0	9
Share-based compensation	1,881	1,727
Excess tax benefit from share-based compensation	(265)	(56)
Changes in certain operating assets and liabilities:
Trade accounts receivable	(49,545)	(53,079)
Income taxes receivable	1,038	12,003
Prepaid expenses and other	(464)	(455)
Accounts payable	1,303	463
Accrued payroll, payroll taxes and related benefits	39,719	45,290
Other accrued liabilities	4,585	(3,847)
Income taxes payable	5,062	4,478
Workers' compensation claims liabilities	36,256	22,493
Safety incentives liability	3,744	5,728
Customer deposits, long-term liabilities and other assets, net	851	378
Net cash provided by operating activities	57,292	51,290
Cash flows used in investing activities:
Purchase of property and equipment	(5,311)	(1,903)
Proceeds from sale of property and equipment	1,478	0
Purchase of investments	(274)	(2,943)
Proceeds from sales and maturities of investments	4,504	47,797
Purchase of restricted cash and investments	(127,207)	(99,482)
Proceeds from sales and maturities of restricted cash and investments	91,113	25,190
Net cash used in investing activities	(35,697)	(31,341)
Cash flows used in financing activities:
Proceeds from credit-line borrowings	14,868	46,106
Payments on credit-line borrowings	(14,868)	(46,106)
Payments on long-term debt	(15,165)	(10,166)
Common stock repurchased on vesting of restricted stock units	(433)	(465)
Dividends paid	(4,766)	(4,726)
Proceeds from exercise of stock options and vesting of restricted stock units	72	689
Excess tax benefits from share-based compensation	265	56
Net cash used in financing activities	(20,027)	(14,612)
Net increase in cash and cash equivalents	1,568	5,337
Cash and cash equivalents, beginning of period	25,218	11,544
Cash and cash equivalents, end of period	$ 26,786	$ 16,881

Basis of Presentation of Interi

Basis of Presentation of Interim Period Statements	9 Months Ended
	Sep. 30, 2016
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 preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the 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 2015 Annual Report on Form 10-K at pages F1 – F62. The results of operations for an interim period are not necessarily indicative of the results of operations for a full year. Revenue recognition We recognize professional employer (“PEO”) service and staffing service revenue as services are rendered by our workforce. 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. Our client services 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 services agreements provide for immediate termination upon any default of the client regardless of when notice is given. We report PEO revenues on a net basis because we are not the primary obligor for the services provided by our clients to their customers pursuant to our client services agreements. We reduce these service fee revenues by the amounts invoiced to our clients for direct payroll expenses such as salaries, wages, health insurance, employee out-of-pocket expenses incurred incidental to employment, and safety incentives. Safety incentives represent cash incentives paid to certain client companies for maintaining safe-work practices and minimizing workplace injuries. The safety incentive is based on a percentage of annual payroll and is paid annually to clients who meet predetermined workers’ compensation claims cost objectives. Cost of revenues Our cost of revenues for staffing services includes direct payroll costs, employer payroll related taxes, employee benefits, and workers’ compensation costs. Our cost of revenues for PEO services includes only employer payroll related taxes 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 the costs associated with our workers’ compensation program, including claims reserves, claims administration fees, legal fees, medical cost containment (“MCC”) expense, state administrative agency fees, third-party broker commissions, risk manager payroll, and excess insurance premiums for catastrophic injuries. We maintain separate workers’ compensation insurance policies for employees working in states where the Company is not self-insured, including California. Cash and cash equivalents We consider non-restricted short-term investments, which 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 As of September 30, 2016, the Company’s investments consisted of municipal bonds and corporate bonds. We classify our investments as trading or available-for-sale. The Company had no trading securities at September 30, 2016 and December 31, 2015. The Company classifies money market funds, municipal bonds, and corporate bonds 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. Management considers available evidence in evaluating potential impairment of investments, including the duration and extent to which fair value is less than cost. Realized gains and losses on sales of investments are included in other income (expense) as other, net in our condensed consolidated statements of operations. In the event a loss is determined to be other-than-temporary, the loss will be recognized in the condensed consolidated statements of operations. Restricted cash and investments At September 30, 2016, restricted cash and investments consisted of money market funds, certificates of deposit, U.S. Treasuries, corporate bonds, and municipal bonds with maturities generally from 180 days to two years. At September 30, 2016, the approximate fair value of restricted cash and investments equaled their approximate amortized cost. Restricted investments have been 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. Management considers available evidence in evaluating potential impairment of investments, including the duration and extent to which fair value is less than cost. Realized gains and losses on sales of restricted investments are included in other income (expense) as other, net in our condensed consolidated statements of operations. In the event a loss is determined to be other-than-temporary, the loss will be recognized in the condensed consolidated statements of operations. Allowance for doubtful accounts The Company had an allowance for doubtful accounts of $195,000 and $268,000 at September 30, 2016 and December 31, 2015, respectively. We make estimates of the collectability of our accounts receivable for services provided to our customers. 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 internal claims adjusters and our third-party administrators for workers’ compensation claims, coupled with an actuarial estimate of future adverse cost development with respect to reported claims and incurred but not reported claims (together, “IBNR”). At September 30, 2016 and December 31, 2015, workers’ compensation claims liabilities included case reserve estimates for reported losses, plus additional amounts for estimated future adverse cost development of IBNR claims, MCC and legal costs, and unallocated loss adjustment expenses, including future administrative fees to be paid to third-party service providers. 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, changes in individuals involved in the reserve estimation process, 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. The Company’s independent actuary provides management with an estimate of the current and long-term portions of our total workers’ compensation claims, which is an important factor in our process for estimating workers’ compensation claims liabilities. The current portion represents the independent actuary’s best estimate of payments the Company will make related to workers’ compensation claims over the ensuing twelve months. The Company will also pay out a portion of claims first incurred in the ensuing twelve months during that twelve-month period. The long-term portion represents the independent actuary’s best estimate of payments the Company will make related to workers’ compensation claims more than twelve months in the future. 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 liability Safety incentives represent cash incentives paid to certain PEO client companies for maintaining safe-work practices and minimizing workplace injuries. The incentive is based on a percentage of annual payroll and is paid annually to customers who meet predetermined workers’ compensation claims cost objectives. Safety incentive payments are made only after closure of all workers’ compensation claims incurred during the customer’s contract period. The safety incentive liability is estimated and accrued each month based upon contract year-to-date payroll and the then current amount of the customer’s estimated workers’ compensation claims reserves as established by us and our third-party administrator and the expected payout as determined by historical incentive payment trends. The Company provided $25.0 million and $21.3 million at September 30, 2016 and December 31, 2015, respectively, as an estimate of the liability for unpaid safety incentives. Safety incentive costs are netted against PEO service revenue in our condensed consolidated statements of operations. Statements of cash flows Interest paid during the nine months ended September 30, 2016 and 2015 did not materially differ from interest expense. Income taxes received during the nine months ended September 30, 2016 and 2015 totaled $1.1 million and $9.2 million, respectively. 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 stock options and the payment of stock awards from other share-based compensation plans that are outstanding at the end of each period presented. Basic and diluted shares outstanding are summarized as follows (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 Weighted average number of basic shares outstanding 7,243 7,201 7,220 7,163 Effect of dilutive securities 162 161 130 177 Weighted average number of diluted shares outstanding 7,405 7,362 7,350 7,340 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 all investments, allowance for doubtful accounts, deferred income taxes, carrying values for goodwill and property and equipment, accrued workers’ compensation liabilities and safety incentive liabilities. Actual results may differ from such estimates. Recent accounting pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). The amendments in ASU 2014-09 provide for a single, principles-based model for revenue recognition that replaces the existing revenue recognition guidance. In August 2015, the FASB issued ASU 2015-14 which defers the effective date of ASU 2014-09 by one year. ASU 2014-09 is discussed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015. In March and April 2016, the FASB issued ASU 2016-08 Principal versus Agent Considerations (Reporting Revenue Gross versus Net), ASU 2016-10 Identifying Performance Obligations and Licensing, ASU 2016-11 Revenue Recognition and Derivatives and Hedging: Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting, and ASU 2016-12 Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients, which all provide further clarification to be considered when implementing ASU 2014-09. The new guidance is effective for interim and annual reporting periods beginning after December 15, 2017. Early adoption is permitted as of the date of the original effective date, for interim and annual reporting periods beginning after December 15, 2016. The Company plans to adopt this ASU on January 1, 2018 and is in the process of evaluating its planned transition method and the impact to its consolidated financial statements and disclosures of the adoption of ASU 2014-09. In April 2015, the FASB issued Accounting Standards Update No. 2015-03, Interest—Imputation of Interest (“ASU 2015-03”) to simplify the presentation of debt issuance costs. ASU 2015-03 requires debt issuance costs be presented on the balance sheet as a direct reduction from the carrying amount of the related debt liability. The amendments in this accounting standard update are to be applied retrospectively and are effective for interim and annual reporting periods beginning after December 15, 2015. We do not expect the adoption of this accounting standard update to have a material impact on our consolidated financial statements and disclosures. In May 2015, the FASB issued ASU 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) (“ASU 2015-07”). ASU 2015-07 provides that investments for which the practical expedient is used to measure fair value at net asset value per share (“NAV”) must be removed from the fair value hierarchy. Instead, those investments must be included as a reconciling line item so that the total fair value amount of investments in the disclosure is consistent with the amount on the balance sheet. ASU 2015-07 also includes disclosure requirements for investments for which the NAV practical expedient was used to determine fair value. The adoption of this guidance in the third quarter of 2016 did not impact our financial condition or results of operations. In November 2015, the FASB issued Accounting Standards Update No. 2015-17, Balance Sheet Classification of Deferred Taxes (“ASU 2015-17”). ASU 2015-17 requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. The guidance becomes effective for the Company beginning with our annual report for the year ending December 31, 2017 with early adoption permitted. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements and disclosures. In February 2016, the FASB issued ASU 2016-02, Leases (“ASU 2016-02”). ASU 2016-02 requires a lessee to record a right of use asset and a corresponding lease liability on the balance sheet for all leases with terms longer than 12 months. ASU 2016-02 is effective for all interim and annual reporting periods beginning after December 15, 2018. Early adoption is permitted. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company is in the process of evaluating the impact of ASU 2016-02 on the Company’s consolidated financial statements and disclosures. In March 2016, the FASB issued ASU 2016-09, Compensation—Stock Compensation (“ASU 2016-09”). ASU 2016-09 simplifies the accounting for the taxes related to stock-based compensation, including adjustments to how excess tax benefits and a company’s payments for tax withholdings should be classified. This guidance will be effective for fiscal years beginning after December 15, 2016. The Company is currently evaluating the impact that ASU 2016-09 will have on its consolidated financial statements and disclosures. In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments.” ASU No. 2016-15 clarifies and provides specific guidance on eight cash flow classification issues that are not currently addressed by current GAAP, thereby reducing the current diversity in practice. ASU No. 2016-15 is effective for public business entities for annual periods, including interim periods within those annual periods, beginning after December 15, 2017, with early application permitted. This guidance is applicable to the Company’s fiscal year beginning January 1, 2018. The Company is in the process of evaluating the impact of adoption of ASU 2016-15 to the presentation of consolidated cash flows.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurement	Note 2 - Fair Value Measurement The following table summarizes the Company’s investments at September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Cost Gross Recorded Cost Gross Recorded Current: Cash Equivalents: Money Market Funds $ 176 $ 0 $ 176 $ 21,312 $ 0 $ 21,312 Investments: Municipal Bonds 838 0 838 0 0 0 Corporate Bonds 175 0 175 0 0 0 Restricted cash and investments: Money Market Funds 51,959 0 51,959 76,023 0 76,023 Certificate of Deposit 0 0 0 10,000 0 10,000 Total Current Investments 53,148 0 53,148 107,335 0 107,335 Long term: Investments: Corporate Bonds 624 1 625 2,970 (24 ) 2,946 Municipal Bonds 238 0 238 3,135 (3 ) 3,132 Money Market Funds 0 0 0 4 0 4 Restricted cash and investments (1) Money Market Funds 221,901 0 221,901 175,869 0 175,869 Certificates of Deposit 11,776 0 11,776 496 (1 ) 495 U.S. Treasuries 5,258 23 5,281 4,752 1 4,753 Corporate Bonds 3,191 14 3,205 2,996 (24 ) 2,972 Municipal Bonds 2,547 4 2,551 3,613 (1 ) 3,612 Total Long Term Investments 245,535 42 245,577 193,835 (52 ) 193,783 Total Investments $ 298,683 $ 42 $ 298,725 $ 301,170 $ (52 ) $ 301,118 (1) Restricted cash and investments also includes $306,000 of workers’ compensation deposits. The following table summarizes the Company’s investments at September 30, 2016 and December 31, 2015 measured at fair value on a recurring basis by fair value hierarchy level (in thousands): September 30, 2016 December 31, 2015 Total Level 1 Level 2 Level 3 Other (1) Total Level 1 Level 2 Level 3 Other (1) Cash Equivalents: Money Market Funds $ 176 $ 0 $ 0 $ 0 $ 176 $ 21,312 $ 0 $ 0 $ 0 $ 21,312 Investments: Municipal Bonds 1,076 50 1,026 0 0 3,132 241 2,891 0 0 Corporate Bonds 800 502 298 0 0 2,946 2,291 655 0 0 Money Market Funds 0 0 0 0 0 4 0 0 0 4 Restricted cash and investments: Money Market Funds 273,860 0 0 0 273,860 251,892 0 0 0 251,892 Certificates of Deposit 11,776 0 11,776 0 0 10,495 0 10,495 0 0 U.S. Treasuries 5,281 5,281 0 0 0 4,753 4,753 0 0 0 Corporate Bonds 3,205 2,163 1,042 0 0 2,972 2,285 687 0 0 Municipal Bonds 2,551 214 2,337 0 0 3,612 389 3,223 0 0 Total Investments $ 298,725 $ 8,210 $ 16,479 $ 0 $ 274,036 $ 301,118 $ 9,959 $ 17,951 $ 0 $ 273,208 (1) In accordance with ASU 2015-07 (see Note 1), investments in money market funds measured at fair value using the NAV 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.

Workers' Compensation Claims

Workers' Compensation Claims	9 Months Ended
	Sep. 30, 2016
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 2016 2015 2016 2015 Beginning balance Workers’ compensation claims liabilities $ 277,050 $ 239,245 $ 255,675 $ 225,278 Add: claims expense accrual: Current period 38,094 29,723 103,875 84,943 Prior periods (999 ) (2,424 ) (1,547 ) (9,659 ) 37,095 27,299 102,328 75,284 Less: claim payments related to: Current period 5,596 4,974 10,565 8,730 Prior periods 16,618 13,799 55,507 44,061 22,214 18,773 66,072 52,791 Ending balance Workers’ compensation claims liabilities $ 291,931 $ 247,771 $ 291,931 $ 247,771 Incurred but not reported (IBNR) $ 145,722 $ 125,574 $ 145,722 $ 125,574 The states of California, Maryland, Oregon, Washington, Colorado and Delaware required us to maintain specified investment balances or other financial instruments totaling $159.0 million at September 30, 2016 to cover potential workers’ compensation claims losses related to the Company’s current and former status as a self-insured employer. In addition to restricted cash and investments held to satisfy these requirements at September 30, 2016, we have provided surety bonds and standby letters of credit totaling $152.9 million, including a California requirement of $147.2 million. The Company also operates a wholly owned insurance company, Ecole Insurance Company (“Ecole”). Ecole is a fully licensed insurance company holding a certificate of authority from the Arizona Department of Insurance. Ecole provides workers’ compensation coverage to the Company’s employees working in Arizona, Utah and Nevada. The surplus of Ecole was $10.8 million and $9.5 million at September 30, 2016 and December 31, 2015, respectively, and is included in long-term restricted cash and investments in our condensed consolidated balance sheets. As part of its fronted workers’ compensation insurance program with Chubb Limited (“Chubb”, formerly ACE Group) in the states of California, Delaware, Virginia, Pennsylvania, North Carolina, New Jersey, West Virginia and the District of Columbia, the Company makes payments into a trust account (“the Chubb trust account”) to be used for the payment of future claims. The balance in the Chubb trust account was $235.2 million and $166.6 million at September 30, 2016 and December 31, 2015, respectively. The Chubb trust account balances are included as a component of the current and long-term restricted cash and investments in the Company’s condensed consolidated balance sheets. Note 3 - Workers’ Compensation Claims (Continued) At September 30, 2016 the Company recorded an asset of $13.2 million related to a payment remitted to Chubb on September 29, 2016 but not deposited into the Chubb trust account until October 2016. This amount is included in other assets in the condensed consolidated balance sheet.

Revolving Credit Facility and L

Revolving Credit Facility and Long-Term Debt	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Revolving Credit Facility and Long-Term Debt	Note 4 - Revolving Credit Facility and Long-Term Debt The Company maintains a credit agreement (the “Agreement”) with its principal bank, Wells Fargo Bank, National Association (the “Bank”). The Agreement provided for a $40.0 million term loan maturing December 31, 2016, as well as a $14.0 million revolving credit line, with a $6.0 million sublimit for unsecured standby letters of credit. As of September 30, 2016, the term loan has been paid off completely, compared to an outstanding balance of $15.0 million at December 31, 2015. The Agreement also included $42.3 million in cash-secured letters of credit at September 30, 2016 to satisfy collateral requirements associated with the Company’s former status as a self-insured employer in California. In conjunction with these letters of credit, the Company posted with the Bank as collateral $44.1 million in restricted money market funds and restricted certificates of deposit. Advances under the revolving credit facility bear interest as selected by the Company of either (a) a daily floating rate of one month LIBOR plus 2.0% or (b) a fixed rate of LIBOR plus 2.0%. The Agreement also provides for an unused commitment fee of 0.35% per year on the average daily unused amount of the revolving credit facility, and a fee of 1.75% of the face amount of each letter of credit. The Company had no outstanding borrowings on its revolving credit line at September 30, 2016 and December 31, 2015. The revolving credit line expires on October 1, 2017. The credit facility is collateralized by the Company’s accounts receivable and other rights to receive payment, general intangibles and equipment. The Agreement requires the satisfaction of certain financial covenants as follows: • minimum Fixed Charge Coverage ratio of no less than 2.25:1.0, measured quarterly on a rolling four-quarter basis, with Fixed Charge Coverage Ratio defined as (i) EBITDA (net profit before taxes plus interest expense, net of capitalized interest expense, depreciation expense and amortization expense) minus distributions, dividends and cash taxes paid, divided by (ii) $9,425,000. Prior to September 30, 2016, the minimum Fixed Charge Coverage ratio was no less than 1.50:1.0, measured quarterly on a rolling four-quarter basis. • ratio of restricted and unrestricted cash and investments to workers’ compensation and safety incentive liabilities of at least 1.0:1.0, measured quarterly. The Agreement includes certain additional restrictions as follows: • capital expenditures may not exceed a total of $4.0 million in 2016 without the Bank’s prior approval; • incurring additional indebtedness is prohibited without the prior approval of the Bank, other than up to $200,000 per year in purchase money financing and the aggregate of all purchase money indebtedness may not exceed $400,000 at any time; • repurchases of the Company’s common stock are prohibited. • quarterly cash dividends up to $0.22 per share may be paid so long as there is no default by the Company and payment would not cause a default; and • delisting of the Company’s common stock by The Nasdaq Stock Market (“Nasdaq”) is an event of default. The Agreement also contains customary events of default. 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, 2016, the Company was in violation of the capital expenditure restriction. The Bank agreed to waive this covenant violation. The Company maintains a mortgage loan with the Bank with a balance of approximately $4.7 million and $4.8 million at September 30, 2016 and December 31, 2015, respectively, secured by the Company’s corporate office building in Vancouver, Washington. This loan requires payment of monthly principal payments of $18,375 plus interest at a rate of one month LIBOR plus 2.25%, with the unpaid principal balance due November 1, 2017.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
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, 2016. Based on management’s analysis, no valuation allowance of deferred tax assets was recorded at September 30, 2016. The Internal Revenue Service is examining the Company’s federal tax returns for the years ended December 31, 2011, 2012, 2013 and 2014.

Litigation

Litigation	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Litigation	Note 6 - Litigation On November 6, 2014, plaintiffs in Michael Arciaga, et al. v. Barrett Business Services, Inc., et al. On November 13, 2014, a second purported shareholder class action was filed in the United States District Court for the Western District of Washington, entitled Christopher P. Carnes, et al. v. Barrett Business Services, Inc., et al Carnes Arciaga Similarly, on November 17, 2014, a third purported shareholder class action was filed in the United States District Court for the Western District of Washington, entitled Shiva Stein, et al. v. Barrett Business Services, Inc., et al. Stein Arciaga Carnes On February 25, 2015, the court ordered consolidation of the three cases, and any new or other cases involving the same subject matter, into a single action for pretrial purposes. The consolidated cases were recaptioned as In re Barrett Business Services Securities Litigation. On March 21, 2016, before the court had ruled on the defendants’ motion to dismiss the plaintiffs’ first amended consolidated complaint, the plaintiffs filed a second amended consolidated complaint, naming the same defendants. The second amended consolidated complaint dropped certain allegations from the first amended complaint and added new allegations relating to disclosures in BBSI’s Current Report on Form 8-K filed on March 9, 2016. The defendants filed a motion to dismiss the second amended consolidated complaint on May 23, 2016. On October 26, 2016, before the court ruled on the motion to dismiss, the parties entered into a Stipulation and Agreement of Settlement dated as of October 26, 2016 (the “Settlement”), to settle the litigation. The settlement class includes all persons and entities who purchased or otherwise acquired BBSI common stock in the period beginning February 12, 2013, through March 9, 2016, and were damaged thereby, with certain exclusions. The Settlement is intended to fully, finally and forever compromise, settle, release, resolve, and dismiss with prejudice the purported class action and all claims asserted therein against the named defendants. In the Settlement, the defendants have denied all allegations of wrongdoing and the plaintiffs have not conceded any infirmities in their positions. The Settlement calls for the payment in cash of $12.0 million (the “Settlement Fund”) into escrow by November 29, 2016, which is 15 business days after the court entered an order preliminarily approving the Settlement. Of this amount, approximately $8.7 million will be paid by BBSI’s insurance carriers and approximately $3.3 million will be paid by BBSI. The amount to be paid by BBSI has been accrued at September 30, 2016 and is included in other accrued liabilities in our condensed consolidated balance sheet. The fees of counsel for the plaintiffs will be paid out of the Settlement Fund following approval by the court. The Settlement is subject to approval by the court and to other customary terms and conditions, including the right of BBSI to terminate the Settlement under specified circumstances. All potential class members will be notified of the Settlement in November 2016. The court has scheduled a hearing for February 22, 2017, to consider final approval of the Settlement. If the Settlement is not approved by the court, or is otherwise terminated before it is finalized, BBSI is unable to predict the final outcome of the litigation or to estimate its effect on BBSI, which may be material and adverse. BBSI received a subpoena from the San Francisco office of the Division of Enforcement of the Securities and Exchange Commission (the “SEC”) in May 2015 in connection with the SEC’s investigation of BBSI’s accounting practices with regard to its workers’ compensation reserves. In April 2016, the SEC issued a second subpoena to BBSI for documents relating to the disclosures made by BBSI following Mr. Miller’s termination. BBSI was also advised by the United States Department of Justice in mid-June 2016 that it has commenced an investigation. BBSI is cooperating fully with the investigations. On June 17, 2015, Daniel Salinas (“Salinas”) filed a shareholder derivative lawsuit against BBSI and certain of its officers and directors in the Circuit Court for Baltimore City, Maryland. The complaint alleges breaches of fiduciary duty, unjust enrichment and other violations of law and seeks recovery of various damages, including the costs and expenses incurred in connection with BBSI’s reserve strengthening process, reserve study and consultants, the cost of stock repurchases by BBSI in October 2014, compensation paid to BBSI’s officers, and costs of negotiating BBSI’s credit facility with its principal lender, as well as the proceeds of sales of stock by certain of BBSI’s officers and directors during 2013 and 2014. On September 28, 2015, BBSI and the individual defendants filed motions to dismiss the derivative suit and a motion to stay pending resolution of In re Barrett Business Services Securities Litigation Management is unable to estimate the probability, or the potential range of loss arising from the legal actions described above. BBSI is subject to other legal proceedings and claims, which arise in the ordinary course of our business. In the opinion of management, the amount of ultimate liability with respect to other currently pending or threatened actions is not expected to materially affect BBSI’s consolidated financial position or results of operations.

Basis of Presentation of Inte15

Basis of Presentation of Interim Period Statements (Policies)	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Revenue recognition	Revenue recognition We recognize professional employer (“PEO”) service and staffing service revenue as services are rendered by our workforce. 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. Our client services 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 services agreements provide for immediate termination upon any default of the client regardless of when notice is given. We report PEO revenues on a net basis because we are not the primary obligor for the services provided by our clients to their customers pursuant to our client services agreements. We reduce these service fee revenues by the amounts invoiced to our clients for direct payroll expenses such as salaries, wages, health insurance, employee out-of-pocket expenses incurred incidental to employment, and safety incentives. Safety incentives represent cash incentives paid to certain client companies for maintaining safe-work practices and minimizing workplace injuries. The safety incentive is based on a percentage of annual payroll and is paid annually to clients who meet predetermined workers’ compensation claims cost objectives.
Cost of revenues	Cost of revenues Our cost of revenues for staffing services includes direct payroll costs, employer payroll related taxes, employee benefits, and workers’ compensation costs. Our cost of revenues for PEO services includes only employer payroll related taxes 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 the costs associated with our workers’ compensation program, including claims reserves, claims administration fees, legal fees, medical cost containment (“MCC”) expense, state administrative agency fees, third-party broker commissions, risk manager payroll, and excess insurance premiums for catastrophic injuries. We maintain separate workers’ compensation insurance policies for employees working in states where the Company is not self-insured, including California.
Cash and cash equivalents	Cash and cash equivalents We consider non-restricted short-term investments, which 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 As of September 30, 2016, the Company’s investments consisted of municipal bonds and corporate bonds. We classify our investments as trading or available-for-sale. The Company had no trading securities at September 30, 2016 and December 31, 2015. The Company classifies money market funds, municipal bonds, and corporate bonds 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. Management considers available evidence in evaluating potential impairment of investments, including the duration and extent to which fair value is less than cost. Realized gains and losses on sales of investments are included in other income (expense) as other, net in our condensed consolidated statements of operations. In the event a loss is determined to be other-than-temporary, the loss will be recognized in the condensed consolidated statements of operations.
Restricted cash and investments	Restricted cash and investments At September 30, 2016, restricted cash and investments consisted of money market funds, certificates of deposit, U.S. Treasuries, corporate bonds, and municipal bonds with maturities generally from 180 days to two years. At September 30, 2016, the approximate fair value of restricted cash and investments equaled their approximate amortized cost. Restricted investments have been 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. Management considers available evidence in evaluating potential impairment of investments, including the duration and extent to which fair value is less than cost. Realized gains and losses on sales of restricted investments are included in other income (expense) as other, net in our condensed consolidated statements of operations. In the event a loss is determined to be other-than-temporary, the loss will be recognized in the condensed consolidated statements of operations.
Allowance for doubtful accounts	Allowance for doubtful accounts The Company had an allowance for doubtful accounts of $195,000 and $268,000 at September 30, 2016 and December 31, 2015, respectively. We make estimates of the collectability of our accounts receivable for services provided to our customers. 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 internal claims adjusters and our third-party administrators for workers’ compensation claims, coupled with an actuarial estimate of future adverse cost development with respect to reported claims and incurred but not reported claims (together, “IBNR”). At September 30, 2016 and December 31, 2015, workers’ compensation claims liabilities included case reserve estimates for reported losses, plus additional amounts for estimated future adverse cost development of IBNR claims, MCC and legal costs, and unallocated loss adjustment expenses, including future administrative fees to be paid to third-party service providers. 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, changes in individuals involved in the reserve estimation process, 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. The Company’s independent actuary provides management with an estimate of the current and long-term portions of our total workers’ compensation claims, which is an important factor in our process for estimating workers’ compensation claims liabilities. The current portion represents the independent actuary’s best estimate of payments the Company will make related to workers’ compensation claims over the ensuing twelve months. The Company will also pay out a portion of claims first incurred in the ensuing twelve months during that twelve-month period. The long-term portion represents the independent actuary’s best estimate of payments the Company will make related to workers’ compensation claims more than twelve months in the future. 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 liability	Safety incentives liability Safety incentives represent cash incentives paid to certain PEO client companies for maintaining safe-work practices and minimizing workplace injuries. The incentive is based on a percentage of annual payroll and is paid annually to customers who meet predetermined workers’ compensation claims cost objectives. Safety incentive payments are made only after closure of all workers’ compensation claims incurred during the customer’s contract period. The safety incentive liability is estimated and accrued each month based upon contract year-to-date payroll and the then current amount of the customer’s estimated workers’ compensation claims reserves as established by us and our third-party administrator and the expected payout as determined by historical incentive payment trends. The Company provided $25.0 million and $21.3 million at September 30, 2016 and December 31, 2015, respectively, as an estimate of the liability for unpaid safety incentives. Safety incentive costs are netted against PEO service revenue in our condensed consolidated statements of operations.
Statements of cash flows	Statements of cash flows Interest paid during the nine months ended September 30, 2016 and 2015 did not materially differ from interest expense. Income taxes received during the nine months ended September 30, 2016 and 2015 totaled $1.1 million and $9.2 million, respectively.
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 stock options and the payment of stock awards from other share-based compensation plans that are outstanding at the end of each period presented. Basic and diluted shares outstanding are summarized as follows (in thousands): Three Months Ended Nine Months Ended 2016 2015 2016 2015 Weighted average number of basic shares outstanding 7,243 7,201 7,220 7,163 Effect of dilutive securities 162 161 130 177 Weighted average number of diluted shares outstanding 7,405 7,362 7,350 7,340
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 all investments, allowance for doubtful accounts, deferred income taxes, carrying values for goodwill and property and equipment, accrued workers’ compensation liabilities and safety incentive liabilities. Actual results may differ from such estimates.
Recent accounting pronouncements	Recent accounting pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). The amendments in ASU 2014-09 provide for a single, principles-based model for revenue recognition that replaces the existing revenue recognition guidance. In August 2015, the FASB issued ASU 2015-14 which defers the effective date of ASU 2014-09 by one year. ASU 2014-09 is discussed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015. In March and April 2016, the FASB issued ASU 2016-08 Principal versus Agent Considerations (Reporting Revenue Gross versus Net), ASU 2016-10 Identifying Performance Obligations and Licensing, ASU 2016-11 Revenue Recognition and Derivatives and Hedging: Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting, and ASU 2016-12 Revenue from Contracts with Customers: Narrow-Scope Improvements and Practical Expedients, which all provide further clarification to be considered when implementing ASU 2014-09. The new guidance is effective for interim and annual reporting periods beginning after December 15, 2017. Early adoption is permitted as of the date of the original effective date, for interim and annual reporting periods beginning after December 15, 2016. The Company plans to adopt this ASU on January 1, 2018 and is in the process of evaluating its planned transition method and the impact to its consolidated financial statements and disclosures of the adoption of ASU 2014-09. In April 2015, the FASB issued Accounting Standards Update No. 2015-03, Interest—Imputation of Interest (“ASU 2015-03”) to simplify the presentation of debt issuance costs. ASU 2015-03 requires debt issuance costs be presented on the balance sheet as a direct reduction from the carrying amount of the related debt liability. The amendments in this accounting standard update are to be applied retrospectively and are effective for interim and annual reporting periods beginning after December 15, 2015. We do not expect the adoption of this accounting standard update to have a material impact on our consolidated financial statements and disclosures. In May 2015, the FASB issued ASU 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) (“ASU 2015-07”). ASU 2015-07 provides that investments for which the practical expedient is used to measure fair value at net asset value per share (“NAV”) must be removed from the fair value hierarchy. Instead, those investments must be included as a reconciling line item so that the total fair value amount of investments in the disclosure is consistent with the amount on the balance sheet. ASU 2015-07 also includes disclosure requirements for investments for which the NAV practical expedient was used to determine fair value. The adoption of this guidance in the third quarter of 2016 did not impact our financial condition or results of operations. In November 2015, the FASB issued Accounting Standards Update No. 2015-17, Balance Sheet Classification of Deferred Taxes (“ASU 2015-17”). ASU 2015-17 requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. The guidance becomes effective for the Company beginning with our annual report for the year ending December 31, 2017 with early adoption permitted. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements and disclosures. In February 2016, the FASB issued ASU 2016-02, Leases (“ASU 2016-02”). ASU 2016-02 requires a lessee to record a right of use asset and a corresponding lease liability on the balance sheet for all leases with terms longer than 12 months. ASU 2016-02 is effective for all interim and annual reporting periods beginning after December 15, 2018. Early adoption is permitted. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company is in the process of evaluating the impact of ASU 2016-02 on the Company’s consolidated financial statements and disclosures. In March 2016, the FASB issued ASU 2016-09, Compensation—Stock Compensation (“ASU 2016-09”). ASU 2016-09 simplifies the accounting for the taxes related to stock-based compensation, including adjustments to how excess tax benefits and a company’s payments for tax withholdings should be classified. This guidance will be effective for fiscal years beginning after December 15, 2016. The Company is currently evaluating the impact that ASU 2016-09 will have on its consolidated financial statements and disclosures. In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments.” ASU No. 2016-15 clarifies and provides specific guidance on eight cash flow classification issues that are not currently addressed by current GAAP, thereby reducing the current diversity in practice. ASU No. 2016-15 is effective for public business entities for annual periods, including interim periods within those annual periods, beginning after December 15, 2017, with early application permitted. This guidance is applicable to the Company’s fiscal year beginning January 1, 2018. The Company is in the process of evaluating the impact of adoption of ASU 2016-15 to the presentation of consolidated cash flows.

Basis of Presentation of Inte16

Basis of Presentation of Interim Period Statements (Tables)	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
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 2016 2015 2016 2015 Weighted average number of basic shares outstanding 7,243 7,201 7,220 7,163 Effect of dilutive securities 162 161 130 177 Weighted average number of diluted shares outstanding 7,405 7,362 7,350 7,340

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Summary of Investments	The following table summarizes the Company’s investments at September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Cost Gross Recorded Cost Gross Recorded Current: Cash Equivalents: Money Market Funds $ 176 $ 0 $ 176 $ 21,312 $ 0 $ 21,312 Investments: Municipal Bonds 838 0 838 0 0 0 Corporate Bonds 175 0 175 0 0 0 Restricted cash and investments: Money Market Funds 51,959 0 51,959 76,023 0 76,023 Certificate of Deposit 0 0 0 10,000 0 10,000 Total Current Investments 53,148 0 53,148 107,335 0 107,335 Long term: Investments: Corporate Bonds 624 1 625 2,970 (24 ) 2,946 Municipal Bonds 238 0 238 3,135 (3 ) 3,132 Money Market Funds 0 0 0 4 0 4 Restricted cash and investments (1) Money Market Funds 221,901 0 221,901 175,869 0 175,869 Certificates of Deposit 11,776 0 11,776 496 (1 ) 495 U.S. Treasuries 5,258 23 5,281 4,752 1 4,753 Corporate Bonds 3,191 14 3,205 2,996 (24 ) 2,972 Municipal Bonds 2,547 4 2,551 3,613 (1 ) 3,612 Total Long Term Investments 245,535 42 245,577 193,835 (52 ) 193,783 Total Investments $ 298,683 $ 42 $ 298,725 $ 301,170 $ (52 ) $ 301,118 (1) Restricted cash and investments also includes $306,000 of workers’ compensation deposits.
Summary of Assets Measured at Fair Value on Recurring Basis	The following table summarizes the Company’s investments at September 30, 2016 and December 31, 2015 measured at fair value on a recurring basis by fair value hierarchy level (in thousands): September 30, 2016 December 31, 2015 Total Level 1 Level 2 Level 3 Other (1) Total Level 1 Level 2 Level 3 Other (1) Cash Equivalents: Money Market Funds $ 176 $ 0 $ 0 $ 0 $ 176 $ 21,312 $ 0 $ 0 $ 0 $ 21,312 Investments: Municipal Bonds 1,076 50 1,026 0 0 3,132 241 2,891 0 0 Corporate Bonds 800 502 298 0 0 2,946 2,291 655 0 0 Money Market Funds 0 0 0 0 0 4 0 0 0 4 Restricted cash and investments: Money Market Funds 273,860 0 0 0 273,860 251,892 0 0 0 251,892 Certificates of Deposit 11,776 0 11,776 0 0 10,495 0 10,495 0 0 U.S. Treasuries 5,281 5,281 0 0 0 4,753 4,753 0 0 0 Corporate Bonds 3,205 2,163 1,042 0 0 2,972 2,285 687 0 0 Municipal Bonds 2,551 214 2,337 0 0 3,612 389 3,223 0 0 Total Investments $ 298,725 $ 8,210 $ 16,479 $ 0 $ 274,036 $ 301,118 $ 9,959 $ 17,951 $ 0 $ 273,208 (1) In accordance with ASU 2015-07 (see Note 1), investments in money market funds measured at fair value using the NAV 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.

Workers' Compensation Claims (T

Workers' Compensation Claims (Tables)	9 Months Ended
	Sep. 30, 2016
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 2016 2015 2016 2015 Beginning balance Workers’ compensation claims liabilities $ 277,050 $ 239,245 $ 255,675 $ 225,278 Add: claims expense accrual: Current period 38,094 29,723 103,875 84,943 Prior periods (999 ) (2,424 ) (1,547 ) (9,659 ) 37,095 27,299 102,328 75,284 Less: claim payments related to: Current period 5,596 4,974 10,565 8,730 Prior periods 16,618 13,799 55,507 44,061 22,214 18,773 66,072 52,791 Ending balance Workers’ compensation claims liabilities $ 291,931 $ 247,771 $ 291,931 $ 247,771 Incurred but not reported (IBNR) $ 145,722 $ 125,574 $ 145,722 $ 125,574

Basis of Presentation of Inte19

Basis of Presentation of Interim Period Statements - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Basis Of Presentation Of Interim Period Statements [Line Items]
Revenue recognition professional employer services contracts term	1 year
Professional employer service contract cancellation and termination period	30 days
Cash and cash equivalents, maturity term	3 months
Trading securities	$ 0		$ 0
Allowance for doubtful accounts	195,000		268,000
Estimate of liability for unpaid safety incentives	25,000,000		$ 21,300,000
Income taxes received	$ 1,100,000	$ 9,200,000
Minimum [Member]
Basis Of Presentation Of Interim Period Statements [Line Items]
Restricted cash and investments maturity period	180 days
Maximum [Member]
Basis Of Presentation Of Interim Period Statements [Line Items]
Restricted cash and investments maturity period	2 years

Basis of Presentation of Inte20

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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average number of basic shares outstanding	7,243	7,201	7,220	7,163
Effect of dilutive securities	162	161	130	177
Weighted average number of diluted shares outstanding	7,405	7,362	7,350	7,340

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	$ 298,683	$ 301,170
Gross Unrealized Gains (Losses)	42	(52)
Recorded Basis	298,725	301,118
Investments Current [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	53,148	107,335
Gross Unrealized Gains (Losses)	0	0
Recorded Basis	53,148	107,335
Investments Current [Member] | Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	176	21,312
Gross Unrealized Gains (Losses)	0	0
Recorded Basis	176	21,312
Investments Current [Member] | Investments [Member] | Municipal Bonds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	838	0
Gross Unrealized Gains (Losses)	0	0
Recorded Basis	838	0
Investments Current [Member] | Investments [Member] | Corporate Bonds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	175	0
Gross Unrealized Gains (Losses)	0	0
Recorded Basis	175	0
Investments Current [Member] | Restricted Cash and Investments [Member] | Money Market Funds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	51,959	76,023
Gross Unrealized Gains (Losses)	0	0
Recorded Basis	51,959	76,023
Investments Current [Member] | Restricted Cash and Investments [Member] | Certificates of Deposit [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	0	10,000
Gross Unrealized Gains (Losses)	0	0
Recorded Basis	0	10,000
Investments Noncurrent [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	245,535	193,835
Gross Unrealized Gains (Losses)	42	(52)
Recorded Basis	245,577	193,783
Investments Noncurrent [Member] | Investments [Member] | Money Market Funds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	0	4
Gross Unrealized Gains (Losses)	0	0
Recorded Basis	0	4
Investments Noncurrent [Member] | Investments [Member] | Municipal Bonds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	238	3,135
Gross Unrealized Gains (Losses)	0	(3)
Recorded Basis	238	3,132
Investments Noncurrent [Member] | Investments [Member] | Corporate Bonds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	624	2,970
Gross Unrealized Gains (Losses)	1	(24)
Recorded Basis	625	2,946
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Money Market Funds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	221,901	175,869
Gross Unrealized Gains (Losses)	0	0
Recorded Basis	221,901	175,869
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Certificates of Deposit [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	11,776	496
Gross Unrealized Gains (Losses)	0	(1)
Recorded Basis	11,776	495
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Municipal Bonds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	2,547	3,613
Gross Unrealized Gains (Losses)	4	(1)
Recorded Basis	2,551	3,612
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	3,191	2,996
Gross Unrealized Gains (Losses)	14	(24)
Recorded Basis	3,205	2,972
Investments Noncurrent [Member] | Restricted Cash and Investments [Member] | U.S. Treasuries [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Cost	5,258	4,752
Gross Unrealized Gains (Losses)	23	1
Recorded Basis	$ 5,281	$ 4,753

Fair Value Measurement - Summ22

Fair Value Measurement - Summary of Investments (Parenthetical) (Detail)	Sep. 30, 2016USD ($)
Fair Value Disclosures [Abstract]
Workers compensation deposits	$ 306,000

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	$ 298,725	$ 301,118
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	176	21,312
Investments [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	4
Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	800	2,946
Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	1,076	3,132
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	273,860	251,892
Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	3,205	2,972
Restricted Cash and Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	2,551	3,612
Restricted Cash and Investments [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	11,776	10,495
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	5,281	4,753
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	8,210	9,959
Level 1 [Member] | 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	0	0
Level 1 [Member] | Investments [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 1 [Member] | Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	502	2,291
Level 1 [Member] | Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	50	241
Level 1 [Member] | 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	0	0
Level 1 [Member] | Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	2,163	2,285
Level 1 [Member] | Restricted Cash and Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	214	389
Level 1 [Member] | Restricted Cash and Investments [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 1 [Member] | 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	5,281	4,753
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	16,479	17,951
Level 2 [Member] | 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	0	0
Level 2 [Member] | Investments [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 2 [Member] | Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	298	655
Level 2 [Member] | Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	1,026	2,891
Level 2 [Member] | 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	0	0
Level 2 [Member] | Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	1,042	687
Level 2 [Member] | Restricted Cash and Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	2,337	3,223
Level 2 [Member] | Restricted Cash and Investments [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	11,776	10,495
Level 2 [Member] | 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	0	0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 3 [Member] | 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	0	0
Level 3 [Member] | Investments [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 3 [Member] | Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 3 [Member] | Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 3 [Member] | 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	0	0
Level 3 [Member] | Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 3 [Member] | Restricted Cash and Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 3 [Member] | Restricted Cash and Investments [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Level 3 [Member] | 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	0	0
Fair Value Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	274,036	273,208
Fair Value Other [Member] | 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	176	21,312
Fair Value Other [Member] | Investments [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	4
Fair Value Other [Member] | Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Fair Value Other [Member] | Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Fair Value Other [Member] | 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	273,860	251,892
Fair Value Other [Member] | Restricted Cash and Investments [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Fair Value Other [Member] | Restricted Cash and Investments [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Fair Value Other [Member] | Restricted Cash and Investments [Member] | Certificates of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Recorded Basis	0	0
Fair Value Other [Member] | 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	$ 0	$ 0

Workers' Compensation Claims -

Workers' Compensation Claims - Summarizes Aggregate Workers' Compensation Reserve Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Workers Compensation Reserve [Abstract]
Workers' compensation claims liabilities, Beginning balance	$ 277,050	$ 239,245	$ 255,675	$ 225,278
Add: claims expense accrual:
Current period	38,094	29,723	103,875	84,943
Prior periods	(999)	(2,424)	(1,547)	(9,659)
Total expense accrual	37,095	27,299	102,328	75,284
Less: claim payments related to:
Current period	5,596	4,974	10,565	8,730
Prior periods	16,618	13,799	55,507	44,061
Total paid	22,214	18,773	66,072	52,791
Workers' compensation claims liabilities, Ending balance	291,931	247,771	291,931	247,771
Incurred but not reported (IBNR)	$ 145,722	$ 125,574	$ 145,722	$ 125,574

Workers' Compensation Claims 25

Workers' Compensation Claims - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Specified investment balances or other financial instruments	$ 159
Surety bonds and standby letters of credit	152.9
Balance in Chubb trust account	235.2	$ 166.6
Receivable from Chubb	13.2
Ecole Insurance Company [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Surplus from wholly owned subsidiary	10.8	$ 9.5
California [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Surety bonds and standby letters of credit	$ 147.2

Revolving Credit Facility and26

Revolving Credit Facility and Long-Term Debt - Additional Information (Detail) - Agreement [Member] - USD ($)	Sep. 29, 2016	Sep. 30, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Restricted money market funds and restricted certificates of deposit, current		$ 44,100,000
Line of credit facility commitment fee description		The Agreement also provides for an unused commitment fee of 0.35% per year on the average daily unused amount of the revolving credit facility, and a fee of 1.75% of the face amount of each letter of credit
Amount divided to calculate amended fixed charge coverage ratio		$ 9,425,000
Maximum amount of capital expenditures in 2016		$ 4,000,000
Minimum [Member]
Line of Credit Facility [Line Items]
Minimum fixed charge coverage ratio	150.00%	225.00%
Ratio of restricted and unrestricted cash and investments to workers' compensation and safety incentive liabilities		100.00%
Prohibition on incurring additional indebtedness without the prior approval of the Bank in purchase money financing		$ 200,000
Maximum [Member]
Line of Credit Facility [Line Items]
Prohibition on incurring additional indebtedness without the prior approval of the Bank in purchase money financing		$ 400,000
Cash dividend		$ 0.22
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Outstanding balance on term loan and revolving credit facility		$ 0	$ 0
Unused commitment fee on unused amount		0.35%
Credit facility, expiration date		Oct. 1, 2017
Revolving Credit Facility [Member] | Wells Fargo [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity		$ 14,000,000
Revolving Credit Facility [Member] | Daily Floating Rate [Member]
Line of Credit Facility [Line Items]
LIBOR plus rate		2.00%
Term loan from Bank, Interest rate description		A daily floating rate of one month LIBOR plus 2.0%
Revolving Credit Facility [Member] | Fixed Rate [Member]
Line of Credit Facility [Line Items]
LIBOR plus rate		2.00%
Term loan from Bank, Interest rate description		A fixed rate of LIBOR plus 2.0%
Unsecured Letters Of Credit [Member]
Line of Credit Facility [Line Items]
Unused commitment fee on unused amount		1.75%
Term Loan [Member]
Line of Credit Facility [Line Items]
Outstanding balance on term loan and revolving credit facility			15,000,000
Term loan from Bank, Interest rate description		One month LIBOR plus 2.25%
Term loan with principal bank		$ 4,700,000	$ 4,800,000
Payment of monthly principal of term loan		18,375
Term Loan [Member] | Wells Fargo [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity		$ 40,000,000
Term loan maturity date		Dec. 31, 2016
Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
LIBOR plus rate		2.25%
Standby Letters of Credit [Member] | Wells Fargo [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity		$ 6,000,000
Cash-Secured Letters of Credit [Member] | Wells Fargo [Member]
Line of Credit Facility [Line Items]
Credit facility borrowing capacity		$ 42,300,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016USD ($)
Income Tax Contingency [Line Items]
Deferred tax assets, valuation allowance	$ 0
Internal Revenue Service [Member] | Earliest Tax Year [Member]
Income Tax Contingency [Line Items]
Open tax year	2,011
Internal Revenue Service [Member] | Latest Tax Year [Member]
Income Tax Contingency [Line Items]
Open tax year	2,014

Litigation - Additional Informa

Litigation - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)
Loss Contingencies [Line Items]
Settlement amount	$ 12
Settlement payment into escrow	3.3
Insurance Carriers [Member]
Loss Contingencies [Line Items]
Settlement payment into escrow	$ 8.7