Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policie	Summary of Significant Accounting Policies Principles of Consolidation. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated. Use of Estimates. The preparation of financial statements in conformity with generally accepted accounting principles 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 financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Revenue Recognition. Revenues from contract assignments, net of sales adjustments and discounts, are recognized when earned, based on hours worked by the Company’s contract professionals on a weekly basis. Permanent placement revenues are derived from direct hire and conversion fees. Direct hire fees relate to employment candidates that the Company directly places as permanent employees at a client organization. Conversion fees relate to contract professionals on assignment that convert to be permanent employees of the client. Direct hire and conversion fees are recognized as revenues when employment candidates or contract professionals begin permanent employment. The Company records a sales allowance against consolidated revenues, which is an estimate based on historical billing adjustment experience. The billing adjustment reserve includes an allowance for fallouts. Fallouts are permanent placements that do not complete the contingency period, which is typically 90 days or less. The Company includes reimbursed expenses, in revenues and the associated amounts of reimbursable expenses in costs of services. The Company records revenues on a gross basis as a principal or on a net basis as an agent depending on the arrangement. The key indicators as to whether it acts as a principal or an agent are whether the Company (i) has the direct contractual relationships with its customers, (ii) bears the risks and rewards of the transactions and (iii) has the discretion to select the contract professionals and establish their price. Costs of Services. Costs of services include direct costs of contract assignments consisting primarily of payroll, payroll taxes and benefit costs for the Company’s contract professionals. Costs of services also include assignment expenses, many of which are reimbursable by the client. Income Taxes. Income taxes are accounted for using the liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that a portion of the deferred tax asset will not be realized. The Company makes a comprehensive review of its uncertain tax positions regularly. An uncertain tax position represents the Company’s expected treatment of a tax position taken in a filed return, or planned to be taken in a future tax return or claim that has not been reflected in measuring income tax expense for financial reporting purposes. In general, until these positions are sustained by the taxing authorities or statutes expire for the year that the position was taken, the Company does not recognize the tax benefits resulting from such positions and reports the tax effects as a liability for uncertain tax positions. Foreign Currency Translation. The functional currency of the Company’s foreign operations is their local currency, and as such, their assets and liabilities are translated into U.S. dollars at the rate of exchange in effect on the balance sheet date. Revenues and expenses are translated at the average rates of exchange prevailing during each monthly period. The related translation adjustments are recorded as cumulative foreign currency translation adjustments in accumulated other comprehensive income (loss) as a separate component of stockholders’ equity. Gains and losses resulting from foreign currency transactions, which are not material, are included in SG&A expenses in the Consolidated Statements of Operations and Comprehensive Income. Cash and Cash Equivalents. The Company considers all highly liquid investments with a maturity of three months or less on the date of purchase to be cash equivalents. Allowance for Doubtful Accounts and Billing Adjustments. The Company estimates an allowance for doubtful accounts and an allowance for billing adjustments related to trade receivables based on an analysis of historical collection and billing adjustment experience. The Company applies bad debt percentages based on experience to the outstanding accounts receivable balances at the end of the period. The Company also analyzes specific reserves as needed. The allowance for billing adjustments includes a reserve for fallouts which is also based on historical experience. Receivables are written-off when deemed uncollectible. Property and Equipment. Property and equipment are stated at cost. Depreciation and amortization are provided using the straight-line method over the estimated useful lives of the related assets, generally three to five years. Leasehold improvements are amortized over the shorter of the life of the related asset or the remaining term of the lease. Costs associated with customized internal-use software systems that have reached the application development stage and meet recoverability tests are capitalized. Such capitalized costs include external direct costs utilized in developing or obtaining the applications and payroll and payroll-related expenses for employees who are directly associated with the application development. Business Combinations. The purchase price of an acquisition is allocated to the underlying assets acquired and liabilities assumed based upon their estimated fair values at the date of acquisition. To the extent the purchase price exceeds the fair value of the net identifiable tangible and intangible assets acquired and liabilities assumed, such excess is allocated to goodwill. The Company determines the estimated fair values after review and consideration of relevant information including discounted cash flows, quoted market prices and estimates made by management. Accordingly, these can be affected by contract performance and other factors over time, which may cause final amounts to differ materially from original estimates. The Company adjusts the preliminary purchase price allocation, as necessary, up to one year after the acquisition closing date if it obtains more information regarding asset valuations and liabilities assumed. Goodwill acquired in business combinations is assigned to the reporting unit(s) expected to benefit from the combination as of the acquisition date. Acquisition-related costs are recognized separately from the acquisition and are expensed as incurred. Goodwill and Identifiable Intangible Assets. Goodwill and indefinite-lived intangible assets (consisting entirely of trademarks) are tested for impairment on an annual basis as of October 31. Interim testing of goodwill and indefinite-lived intangible assets for impairment is also required whenever an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit or asset below its carrying amount. In order to test the trademarks for impairment, the Company estimates the fair value of the trademarks and compares such amount to their carrying value. The Company estimates the fair value of the trademarks using a projected discounted cash flow analysis, specifically a relief-from-royalty approach. The principal factors used in the discounted cash flow analysis requiring judgment are projected net sales, discount rate, royalty rate and terminal growth assumption. The royalty rates used in the analysis are based on royalty agreements and franchise agreements that have occurred in the staffing and services industries. Based upon the annual trademark impairment tests completed in 2015, 2014 and 2013, there were no indications of impairment of the trademarks, and no impairment charges. Intangible assets having finite lives are amortized over their useful lives and are tested for recoverability whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. Customer relationships are amortized using an accelerated method based on the annual cash flow observed in the initial valuation of the asset. Contractor relationships and non-compete agreements are amortized using the straight-line method. Goodwill is tested for impairment using a two-step process. The first step (Step 1) compares the fair value of a reporting unit to the reporting unit's carrying value. A reporting unit is generally an operating segment or one level below the operating segment level where a business operates and for which discrete financial information is available and reviewed by segment management. If after performing Step 1 of the goodwill impairment test, the fair value of equity of any reporting unit does not exceed its carrying value, the Company performs a second step (Step 2) of the goodwill impairment test for that reporting unit. Step 2 measures the amount of goodwill impairment by comparing the implied fair value of the respective reporting unit goodwill with the carrying value of that goodwill. The reporting unit goodwill impairment loss, if any, is measured as the amount by which the carrying value of goodwill exceeds the implied fair value of goodwill calculated in Step 2 of the goodwill impairment test. Impairment or Disposal of Long-Lived Assets. The Company evaluates long-lived assets, other than goodwill and identifiable intangible assets with indefinite lives, for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. An impairment loss is recognized when the sum of the undiscounted future cash flows is less than the carrying amount of the asset, in which case a write-down is recorded to reduce the related asset to its estimated fair value. There were no significant impairments of long-lived assets in 2015, 2014 and 2013. Workers’ Compensation Loss Reserves. The Company carries retention policies for its workers’ compensation liability exposures. In connection with these programs, the Company pays a base premium plus actual losses incurred, not to exceed certain stop-loss limits. The Company is insured for losses above these limits, both per occurrence and in the aggregate. The workers' compensation loss reserves are based upon an actuarial report obtained from a third party and determined based on claims filed and claims incurred but not reported. The Company accounts for claims incurred but not yet reported based on estimates derived from historical claims experience and current trends of industry data. Changes in estimates and differences in estimates and actual payments for claims are recognized in the period that the estimates changed or the payments were made. Contingencies. The Company records an estimated loss from a loss contingency when information available prior to issuance of its financial statements indicates it is probable that an asset has been impaired or a liability has been incurred at the date of the financial statements, and the amount of the loss can be reasonably estimated. Accounting for contingencies, such as legal settlements, and workers’ compensation matters, requires the Company to use judgment. Stock-Based Compensation. The Company records compensation expense for restricted stock awards and restricted stock units based on the fair market value of the awards on the date of grant. Compensation expense for performance-based awards is measured based on the amount of shares ultimately expected to vest, estimated at each reporting date based on management’s expectations regarding the relevant performance criteria. The Company accounts for stock options granted and employee stock purchase plan shares based on an estimated fair market value using a Black-Scholes option valuation model. This methodology requires the use of subjective assumptions including expected stock price volatility and the estimated life of each award. The fair value of equity-based compensation awards less the estimated forfeitures is amortized over the vesting period of the award. Concentration of Credit Risk. Financial instruments that potentially subject the Company to credit risks consist primarily of cash, cash equivalents and trade receivables. The Company places its cash and cash equivalents in low risk investments with quality credit institutions and limits the amount of credit exposure with any single institution above FDIC insured limits. Concentration of credit risk with respect to accounts receivable is limited because of the large number of geographically dispersed customers, thus spreading the trade credit risk. The Company performs ongoing credit evaluations to identify risks and maintains an allowance to address these risks. Advertising Costs. Advertising costs, which are expensed as incurred, were $3.6 million in 2015, $4.8 million in 2014, and $4.0 million in 2013, and are included in SG&A expenses.

Summary of Significant Accounting Policies

Principles of Consolidation. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated.

Use of Estimates. The preparation of financial statements in conformity with generally accepted accounting principles 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 financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Revenue Recognition. Revenues from contract assignments, net of sales adjustments and discounts, are recognized when earned, based on hours worked by the Company’s contract professionals on a weekly basis. Permanent placement revenues are derived from direct hire and conversion fees. Direct hire fees relate to employment candidates that the Company directly places as permanent employees at a client organization. Conversion fees relate to contract professionals on assignment that convert to be permanent employees of the client. Direct hire and conversion fees are recognized as revenues when employment candidates or contract professionals begin permanent employment. The Company records a sales allowance against consolidated revenues, which is an estimate based on historical billing adjustment experience. The billing adjustment reserve includes an allowance for fallouts. Fallouts are permanent placements that do not complete the contingency period, which is typically 90 days or less. The Company includes reimbursed expenses, in revenues and the associated amounts of reimbursable expenses in costs of services.

The Company records revenues on a gross basis as a principal or on a net basis as an agent depending on the arrangement. The key indicators as to whether it acts as a principal or an agent are whether the Company (i) has the direct contractual relationships with its customers, (ii) bears the risks and rewards of the transactions and (iii) has the discretion to select the contract professionals and establish their price.

Costs of Services. Costs of services include direct costs of contract assignments consisting primarily of payroll, payroll taxes and benefit costs for the Company’s contract professionals. Costs of services also include assignment expenses, many of which are reimbursable by the client.

Income Taxes. Income taxes are accounted for using the liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that a portion of the deferred tax asset will not be realized.

The Company makes a comprehensive review of its uncertain tax positions regularly. An uncertain tax position represents the Company’s expected treatment of a tax position taken in a filed return, or planned to be taken in a future tax return or claim that has not been reflected in measuring income tax expense for financial reporting purposes. In general, until these positions are sustained by the taxing authorities or statutes expire for the year that the position was taken, the Company does not recognize the tax benefits resulting from such positions and reports the tax effects as a liability for uncertain tax positions.

Foreign Currency Translation. The functional currency of the Company’s foreign operations is their local currency, and as such, their assets and liabilities are translated into U.S. dollars at the rate of exchange in effect on the balance sheet date. Revenues and expenses are translated at the average rates of exchange prevailing during each monthly period. The related translation adjustments are recorded as cumulative foreign currency translation adjustments in accumulated other comprehensive income (loss) as a separate component of stockholders’ equity. Gains and losses resulting from foreign currency transactions, which are not material, are included in SG&A expenses in the Consolidated Statements of Operations and Comprehensive Income.

Cash and Cash Equivalents. The Company considers all highly liquid investments with a maturity of three months or less on the date of purchase to be cash equivalents.

Allowance for Doubtful Accounts and Billing Adjustments. The Company estimates an allowance for doubtful accounts and an allowance for billing adjustments related to trade receivables based on an analysis of historical collection and billing adjustment experience. The Company applies bad debt percentages based on experience to the outstanding accounts receivable balances at the end of the period. The Company also analyzes specific reserves as needed. The allowance for billing adjustments includes a reserve for fallouts which is also based on historical experience. Receivables are written-off when deemed uncollectible.

Property and Equipment. Property and equipment are stated at cost. Depreciation and amortization are provided using the straight-line method over the estimated useful lives of the related assets, generally three to five years. Leasehold improvements are amortized over the shorter of the life of the related asset or the remaining term of the lease. Costs associated with customized internal-use software systems that have reached the application development stage and meet recoverability tests are capitalized. Such capitalized costs include external direct costs utilized in developing or obtaining the applications and payroll and payroll-related expenses for employees who are directly associated with the application development.

Business Combinations. The purchase price of an acquisition is allocated to the underlying assets acquired and liabilities assumed based upon their estimated fair values at the date of acquisition. To the extent the purchase price exceeds the fair value of the net identifiable tangible and intangible assets acquired and liabilities assumed, such excess is allocated to goodwill. The Company determines the estimated fair values after review and consideration of relevant information including discounted cash flows, quoted market prices and estimates made by management. Accordingly, these can be affected by contract performance and other factors over time, which may cause final amounts to differ materially from original estimates. The Company adjusts the preliminary purchase price allocation, as necessary, up to one year after the acquisition closing date if it obtains more information regarding asset valuations and liabilities assumed.

Goodwill acquired in business combinations is assigned to the reporting unit(s) expected to benefit from the combination as of the acquisition date. Acquisition-related costs are recognized separately from the acquisition and are expensed as incurred.

Goodwill and Identifiable Intangible Assets. Goodwill and indefinite-lived intangible assets (consisting entirely of trademarks) are tested for impairment on an annual basis as of October 31. Interim testing of goodwill and indefinite-lived intangible assets for impairment is also required whenever an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit or asset below its carrying amount.

In order to test the trademarks for impairment, the Company estimates the fair value of the trademarks and compares such amount to their carrying value. The Company estimates the fair value of the trademarks using a projected discounted cash flow analysis, specifically a relief-from-royalty approach. The principal factors used in the discounted cash flow analysis requiring judgment are projected net sales, discount rate, royalty rate and terminal growth assumption. The royalty rates used in the analysis are based on royalty agreements and franchise agreements that have occurred in the staffing and services industries. Based upon the annual trademark impairment tests completed in 2015, 2014 and 2013, there were no indications of impairment of the trademarks, and no impairment charges.

Intangible assets having finite lives are amortized over their useful lives and are tested for recoverability whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. Customer relationships are amortized using an accelerated method based on the annual cash flow observed in the initial valuation of the asset. Contractor relationships and non-compete agreements are amortized using the straight-line method.

Goodwill is tested for impairment using a two-step process. The first step (Step 1) compares the fair value of a reporting unit to the reporting unit's carrying value. A reporting unit is generally an operating segment or one level below the operating segment level where a business operates and for which discrete financial information is available and reviewed by segment management. If after performing Step 1 of the goodwill impairment test, the fair value of equity of any reporting unit does not exceed its carrying value, the Company performs a second step (Step 2) of the goodwill impairment test for that reporting unit. Step 2 measures the amount of goodwill impairment by comparing the implied fair value of the respective reporting unit goodwill with the carrying value of that goodwill. The reporting unit goodwill impairment loss, if any, is measured as the amount by which the carrying value of goodwill exceeds the implied fair value of goodwill calculated in Step 2 of the goodwill impairment test.

Impairment or Disposal of Long-Lived Assets. The Company evaluates long-lived assets, other than goodwill and identifiable intangible assets with indefinite lives, for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. An impairment loss is recognized when the sum of the undiscounted future cash flows is less than the carrying amount of the asset, in which case a write-down is recorded to reduce the related asset to its estimated fair value. There were no significant impairments of long-lived assets in 2015, 2014 and 2013.

Workers’ Compensation Loss Reserves. The Company carries retention policies for its workers’ compensation liability exposures. In connection with these programs, the Company pays a base premium plus actual losses incurred, not to exceed certain stop-loss limits. The Company is insured for losses above these limits, both per occurrence and in the aggregate. The workers' compensation loss reserves are based upon an actuarial report obtained from a third party and determined based on claims filed and claims incurred but not reported. The Company accounts for claims incurred but not yet reported based on estimates derived from historical claims experience and current trends of industry data. Changes in estimates and differences in estimates and actual payments for claims are recognized in the period that the estimates changed or the payments were made.

Contingencies. The Company records an estimated loss from a loss contingency when information available prior to issuance of its financial statements indicates it is probable that an asset has been impaired or a liability has been incurred at the date of the financial statements, and the amount of the loss can be reasonably estimated. Accounting for contingencies, such as legal settlements, and workers’ compensation matters, requires the Company to use judgment.

Stock-Based Compensation. The Company records compensation expense for restricted stock awards and restricted stock units based on the fair market value of the awards on the date of grant. Compensation expense for performance-based awards is measured based on the amount of shares ultimately expected to vest, estimated at each reporting date based on management’s expectations regarding the relevant performance criteria. The Company accounts for stock options granted and employee stock purchase plan shares based on an estimated fair market value using a Black-Scholes option valuation model. This methodology requires the use of subjective assumptions including expected stock price volatility and the estimated life of each award. The fair value of equity-based compensation awards less the estimated forfeitures is amortized over the vesting period of the award.

Concentration of Credit Risk. Financial instruments that potentially subject the Company to credit risks consist primarily of cash, cash equivalents and trade receivables. The Company places its cash and cash equivalents in low risk investments with quality credit institutions and limits the amount of credit exposure with any single institution above FDIC insured limits. Concentration of credit risk with respect to accounts receivable is limited because of the large number of geographically dispersed customers, thus spreading the trade credit risk. The Company performs ongoing credit evaluations to identify risks and maintains an allowance to address these risks.

Advertising Costs. Advertising costs, which are expensed as incurred, were $3.6 million in 2015, $4.8 million in 2014, and $4.0 million in 2013, and are included in SG&A expenses.