ASGN (ASGN) 8-K 5 Jun 15 2014 FY On Assignment Closes Acquisition of Creative Circle Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 13, 2015	Jun. 30, 2014
Entity Information [Line Items]
Entity Registrant Name	ON ASSIGNMENT INC
Entity Central Index Key	890564
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	8-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		51,531,217
Entity Public Float			$1,759,395,602
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Cash	$28,860,000	$35,024,000
Current Assets:
Accounts receivable, net of allowance of $4,404 and $2,465, respectively	277,146,000	241,905,000
Prepaid expenses and income taxes	13,308,000	7,482,000
Deferred income tax assets	15,746,000	14,374,000
Workers' Compensation and Medical Malpractice Receivable, Current	13,370,000	14,390,000
Other current assets	3,121,000	3,071,000
Disposal Group, Including Discontinued Operation, Assets, Current	34,353,000	34,191,000
Total current assets	385,904,000	350,437,000
Property and equipment, net	44,311,000	36,048,000
Goodwill	512,060,000	514,426,000
Identifiable intangible assets, net	250,609,000	273,623,000
Other non-current assets	7,617,000	8,687,000
Disposal Group, Including Discontinued Operation, Assets, Noncurrent	73,673,000	75,588,000
Total Assets	1,274,174,000	1,258,809,000
Current Liabilities:
Current portion of long-term debt	18,250,000	10,000,000
Accounts payable	7,925,000	7,360,000
Accrued payroll and contract professional pay	82,563,000	72,246,000
Workers’ compensation loss reserves	15,564,000	17,123,000
Income taxes payable	340,000	13,120,000
Other current liabilities	20,729,000	26,460,000
Disposal Group, Including Discontinued Operation, Liabilities, Current	20,195,000	21,986,000
Total current liabilities	165,566,000	168,295,000
Deferred income tax liabilities	63,821,000	46,789,000
Long-term debt	396,875,000	389,813,000
Other long-term liabilities	7,937,000	8,597,000
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	5,567,000	5,182,000
Total liabilities	639,766,000	618,676,000
Commitments and Contingencies (Note 8)	0	0
Stockholders’ equity:
Preferred Stock, $0.01 par value, 1,000,000 shares authorized, no shares issued	0	0
Common Stock, $0.01 par value, 75,000,000 shares authorized, 51,386,693 and 53,926,525 issued and outstanding, respectively	514,000	539,000
Paid-in capital	483,902,000	493,279,000
Retained earnings	154,562,000	146,199,000
Accumulated other comprehensive income (loss)	-4,570,000	116,000
Total stockholders’ equity	634,408,000	640,133,000
Total Liabilities and Stockholders’ Equity	$1,274,174,000	$1,258,809,000

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Allowance for Doubtful Accounts Receivable, Current	$4,404,000	$2,465,000
Stockholders’ equity:
Preferred Stock, par value (in dollars per share)	$0.01	$0.01
Preferred Stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred Stock, shares issued (in shares)	0	0
Preferred Stock, shares outstanding (in shares)	0	0
Common Stock, par value (in dollars per share)	$0.01	$0.01
Common Stock, shares authorized (in shares)	75,000,000	75,000,000
Common Stock, shares issued (in shares)	51,386,693	53,926,525
Common Stock: shares outstanding (in shares)	51,386,693	53,926,525

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Revenues	$1,724,741	$1,523,101	$1,031,935
Cost of services	1,167,306	1,068,226	710,681
Gross profit	557,435	454,875	321,254
Selling, general and administrative expenses	397,523	317,345	231,194
Amortization of intangible assets	22,130	20,943	17,047
Operating income	137,782	116,587	73,013
Interest expense, net	-12,730	-13,931	-12,595
Write-off of loan costs	0	-14,958	-813
Income before income taxes	125,052	87,698	59,605
Provision for income taxes	51,557	36,558	26,142
Income from continuing operations	73,495	51,140	33,463
Gain on sale of discontinued operations, net of income taxes	0	30,840	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	3,689	2,532	9,190
Net income	77,184	84,512	42,653
Basic earnings per common share:
Continuing operations	$1.38	$0.96	$0.72
Discontinued operations	$0.06	$0.62	$0.19
Net income	$1.44	$1.58	$0.91
Diluted earnings per common share:
Continuing operations	$1.35	$0.94	$0.70
Discontinued operations	$0.07	$0.61	$0.19
Net income	$1.42	$1.55	$0.89
Number of shares and share equivalents used to calculate earnings per share:
Basic (in shares)	53,437	53,481	46,739
Diluted (in shares)	54,294	54,555	47,826
Reconciliation of net income to comprehensive income:
Net income	77,184	84,512	42,653
Changes in fair value of derivative, net of tax	86	193	-21
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	-4,772	1,128	854
Comprehensive income	$72,498	$85,833	$43,486

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Changes in fair value of derivative, tax	$86	$193	($21)

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2011	$246,743	$370	$229,377	$19,034	($2,038)
Balance (in shares) at Dec. 31, 2011		37,012,250
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		968,206
Exercise of common stock options	7,041	10	7,031
Employee stock purchase plan (in shares)		154,934
Employee stock purchase plan	1,344	2	1,342
Stock-based compensation expense	9,558		-5,540
Vesting of restricted stock units and restricted stock awards (in shares)		520,652
Vesting of restricted stock units and restricted stock awards	-5,535	5
Tax deficiency from stock-based compensation			4,528
Stock Issued During Period, Shares, Acquisitions		14,304,528
Stock Issued During Period, Value, Acquisitions	225,558	143	225,415
Fair value adjustment of derivatives, net of income tax	-21				-21
Translation adjustments	854				854
Net income (loss)	42,653			42,653
Balance at Dec. 31, 2012	532,723	530	471,711	61,687	-1,205
Balance (in shares) at Dec. 31, 2012		52,960,570
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		393,183
Exercise of common stock options	3,198	3	3,195
Employee stock purchase plan (in shares)		203,200
Employee stock purchase plan	3,856	2	3,854
Stock-based compensation expense	13,911		-4,697
Vesting of restricted stock units and restricted stock awards (in shares)		369,572
Vesting of restricted stock units and restricted stock awards	-4,693	4
Tax deficiency from stock-based compensation			5,305
Fair value adjustment of derivatives, net of income tax	193				193
Translation adjustments	1,128				1,128
Net income (loss)	84,512			84,512
Balance at Dec. 31, 2013	640,133	539	493,279	146,199	116
Balance (in shares) at Dec. 31, 2013	53,926,525	53,926,525
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		147,163
Exercise of common stock options	1,105	1	1,104
Employee stock purchase plan (in shares)		207,805
Employee stock purchase plan	5,253	2	5,251
Stock repurchase and retirement (in shares)	-3,400,000	-3,359,604
Stock repurchase and retirement	-100,048	-33	31,194	68,821
Stock-based compensation expense	17,246		-6,502
Vesting of restricted stock units and restricted stock awards (in shares)		464,804
Vesting of restricted stock units and restricted stock awards	-6,497	5
Tax deficiency from stock-based compensation			4,718
Fair value adjustment of derivatives, net of income tax	86				86
Translation adjustments	-4,772				-4,772
Net income (loss)	77,184			77,184
Balance at Dec. 31, 2014	$634,408	$514	$483,902	$154,562	($4,570)
Balance (in shares) at Dec. 31, 2014	51,386,693	51,386,693

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Cash Flows from Operating Activities:
Net income	$77,184,000	$84,512,000		$42,653,000
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	0	-30,840,000		0
Depreciation and amortization	38,296,000	29,882,000		24,702,000
Allowance for Doubtful Accounts Receivable, Period Increase (Decrease)	7,047,000	1,787,000		-166,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for deferred income taxes	15,948,000	4,111,000		4,970,000
Allocated Share-based Compensation Expense	16,199,000	14,411,000		9,706,000
Write off of Deferred Debt Issuance Cost	0	14,958,000		813,000
Gross excess tax benefits from stock-based compensation	-4,943,000	-5,308,000		-4,638,000
Workersb compensation and medical malpractice provision	3,321,000	5,956,000		3,594,000
Other Noncash Income (Expense)	-1,408,000	1,853,000		-785,000
Changes in operating assets and liabilities, net of effects of acquisitions and divestitures:
Accounts receivable	-45,361,000	-20,155,000		-18,604,000
Prepaid expenses and income taxes	-8,304,000	6,628,000		2,166,000
Increase (Decrease) in Income Taxes Payable	-8,023,000	-5,759,000		196,000
Accounts payable	-1,693,000	-1,580,000		1,987,000
Accrued payroll and contract professional pay	11,275,000	17,554,000		-28,053,000
Increase (Decrease) in Workers' Compensation Liabilities	-2,192,000	-2,348,000		-2,049,000
Deferred compensation	-20,000	-9,980,000		312,000
Other	-4,120,000	8,548,000		2,323,000
Net cash provided by operating activities	96,022,000	110,524,000		40,697,000
Cash Flows from Investing Activities:
Cash paid for property and equipment	-19,729,000	-16,531,000		-14,354,000
Cash paid for acquisitions, net of cash acquired	0	-110,700,000		-347,743,000
Proceeds from Divestiture of Businesses, Net of Cash Divested	0	59,899,000		0
Other	169,000	-1,023,000		-869,000
Net cash used in investing activities	-19,560,000	-68,355,000		-362,966,000
Cash Flows from Financing Activities:
Principal payments of long-term debt	-148,688,000	-456,275,000		-173,163,000
Proceeds from long-term debt	164,000,000	429,500,000		513,000,000
Proceeds from option exercises and employee stock purchase plan	6,358,000	7,054,000		8,384,000
Payment of employment taxes related to release of restricted stock awards	-6,498,000	-7,600,000	[1]	-2,627,000
Gross excess tax benefits from stock-based compensation	4,943,000	5,308,000		4,638,000
Repurchase of common stock	-100,049,000	0		0
Debt issuance or amendment costs	-467,000	-6,938,000		-17,113,000
Payments of accrued earn-outs	-691,000	-3,425,000		-1,198,000
Other	0	-14,000		-43,000
Net cash provided by (used in) financing activities	-81,092,000	-32,390,000		331,878,000
Effect of exchange rate changes on cash and cash equivalents	-1,006,000	92,000		131,000
Net Increase (Decrease) in Cash and Cash Equivalents	-5,636,000	9,871,000		9,740,000
Cash and Cash Equivalents at Beginning of Year (1)	37,350,000	27,479,000		17,739,000
Cash and Cash Equivalents at End of Year (1)	31,714,000	37,350,000		27,479,000
Supplemental Disclosure of Cash Flow Information
Income taxes	56,320,000	32,350,000		33,915,000
Interest	11,559,000	15,158,000		14,722,000
Non-Cash Investing and Financing Activities:
Equity consideration for acquisition	0	0		225,558,000
Payable for employment taxes withheld related to release of restricted stock awards	0	0		2,907,000
Acquisition of property and equipment through accounts payable	2,932,000	594,000		369,000
Acquisition accounting	$0	$0		($1,805,000)
[1]	Cash and cash equivalents at December 31, 2014, 2013, 2012 and 2011 include $2.9 million, $2.3 million, $2.6 million and $4.3 million, respectively, from the Physician Segment (see "Note 5. Discontinued Operations").

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
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. Conversion and direct hire fees are recognized when employment candidates begin permanent employment. The Company records a sales allowance against consolidated revenues, which is an estimate based on historical billing adjustment experience. The sales allowance is recorded as a reduction to revenues and an increase to the allowance for billing adjustments. The billing adjustment reserve includes an allowance for fallouts. Fallouts are direct hire and conversion fees 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 cost 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.
	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. Revenue 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 as a separate component of stockholders’ equity. Gains and losses resulting from foreign currency transactions, which are not material, are included in Selling, general and administrative (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. Receivables, or portions thereof, 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.
	Goodwill and Identifiable Intangible Assets. Goodwill and intangible assets with indefinite lives (consist entirely of trademarks) are tested for impairment on an annual basis as of October 31, and for goodwill whenever an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount and for indefinite lived intangibles, if events or changes in circumstances indicate that it is more likely than not that the asset is impaired.
	In order to test the trademarks for impairment, the Company determines the fair value of the trademarks and compares such amount to its carrying value. The fair value of the trademarks is determined using a projected discounted cash flow analysis based on the 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 value assumption. The royalty rate used in the analysis is based on transactions that have occurred in our industry. 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 relations are amortized using an accelerated method. Contractor relations and non-compete agreements are amortized using the straight-line method. Based upon the annual trademark impairment tests in 2014, 2013 and 2012, there were no trademark impairment charges.
	Goodwill is tested for impairment using a two-step process in which the first step compares the fair value of a reporting unit, which is generally an operating segment or one level below the operating segment level, which is a business and for which discrete financial information is available and reviewed by segment management, to the reporting unit's carrying value. The second step measures the amount of impairment by comparing the implied fair value of the respective reporting unit's goodwill with the carrying value of that goodwill. The goodwill impairment loss is measured by the amount the carrying value of goodwill exceeds the implied fair value of goodwill. Based upon the annual goodwill impairment tests in 2014, 2013 and 2012, there were no goodwill impairment charges.
	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 impairments of long-lived assets in 2014, 2013 and 2012.
	Workers’ Compensation and Medical Malpractice Loss Reserves. The Company carries retention policies for its workers’ compensation liability and medical malpractice 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 and medical malpractice 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, workers’ compensation matters and medical malpractice insurance matters, requires the Company to use judgment.
	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.
	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 $4.8 million in 2014, $4.0 million in 2013, and $3.3 million in 2012, and are included in selling, general and administrative ("SG&A") expenses.
	Reclassifications. Certain prior period amounts have been reclassified to conform to the current period financial statement presentation. These changes consisted of reclassifications to separate certain line items in the accompanying Consolidated Statements of Cash Flows.

Accounting_Standards_Update_No

Accounting Standards Update (Notes)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
New Accounting Pronouncements, Policy [Policy Text Block]	2. Accounting Standards Update
	In April 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity ("ASU 2014-08"). ASU 2014-08 amends the definition of a discontinued operation and requires entities to provide additional disclosures for both discontinued operations and disposal transactions that do not meet the discontinued-operations criteria. It is effective for annual periods beginning on or after December 15, 2014. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial statements.
	In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). ASU 2014-09 improves comparability of revenue recognition practices across entities, industries, jurisdictions and capital markets, and requires entities to provide additional disclosures. It is effective for annual reporting periods beginning after December 15, 2016. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial statements.
	In May 2014, the FASB issued Accounting Standards Update No. 2014-12, Compensation-Stock Compensation (Topic 718) Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period ("ASU 2014-12"). ASU 2014-12 requires that a performance target that affects vesting, and which could be achieved after the requisite service period, be treated as a performance condition. It is effective for annual reporting periods beginning after December 15, 2015. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial statements.
	In January 2015, the FASB issued ASU No. 2015-01, Income Statement - Extraordinary and Unusual Items (Subtopic 225-20), Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items (“ASU No. 2015-01”). ASU No. 2015-01 eliminates from GAAP the concept of extraordinary items to simplify income statement presentation. Under the guidance an entity will no longer be able to segregate an extraordinary item from the results of operations, separately present an extraordinary item on the income statement, or disclose income taxes or earnings-per-share data applicable to an extraordinary item. The ASU is effective for all entities for reporting periods (including interim periods) beginning after December 15, 2015, and early adoption is permitted. The Company will adopt the guidance effective January 1, 2016. The Company does not expect the adoption of ASU No. 2015-01 to have a material effect on its consolidated financial statements.

Property_and_Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property and Equipment.	Property and Equipment
	Property and equipment at December 31, 2014 and 2013 consisted of the following (in thousands):
		2014			2013
	Furniture, fixtures and equipment	$	10,957		$	7,486
	Computers and related equipment	21,741			11,358
	Computer software	41,416			35,943
	Leasehold improvements	5,637			4,711
	Work-in-progress	11,943			14,466
		91,694			73,964
	Less -- accumulated depreciation	(47,383		)	(37,916		)
		$	44,311		$	36,048
	Depreciation expense related to property and equipment was $12.3 million in 2014, $7.2 million in 2013 and $5.7 million in 2012, and is included in SG&A expenses.
	The Company has capitalized costs related to its various technology initiatives. At December 31, 2014 and 2013, the net book value of the property and equipment related to software development was $14.0 million and $13.4 million, respectively, which included work-in-progress of $9.0 million and $10.0 million, respectively.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisitions	Acquisitions
	On December 5, 2013, the Company acquired all of the outstanding shares of CyberCoders Holdings, Inc. ("CyberCoders"), a provider of permanent placement services headquartered in Irvine, California. The primary reason for the acquisition was to expand the Company's permanent placement services. The purchase price was $96.6 million, comprised of $93.6 million in cash paid at closing and estimated future contingent consideration of $3.0 million, which is based on estimated financial performance of CyberCoders through 2015 (the maximum contingent consideration opportunity is $11.0 million). Acquisition costs of approximately $1.5 million were expensed in 2013. Goodwill deductible for tax purposes is $10.3 million for this transaction. The results of operations for the acquisition have been combined with those of the Company from the acquisition date.
	On May 15, 2012, the Company acquired all of the outstanding shares of Apex Systems, Inc. ("Apex Systems"), a privately-owned provider of information technology staffing headquartered in Richmond, Virginia. The primary reason for the acquisition was to expand the Company's information technology staffing services. The purchase price totaled approximately $610.8 million, comprised of $385.0 million paid in cash at closing, $0.3 million paid in the third quarter of 2012 related to the net working capital adjustments, and 14.3 million shares of common stock of the Company issued to the holders of shares of common stock and options to purchase common stock of Apex Systems immediately prior to the effective time of the merger. Acquisition costs related to this transaction totaled approximately $9.8 million and were expensed in 2012. Goodwill and the identifiable intangible assets are deductible for tax purposes. The results of operations of Apex Systems have been combined with those of the Company since the acquisition date.
	Assets and liabilities of the acquired companies were recorded at their estimated fair values at the dates of acquisition. The excess purchase price over the fair value of net tangible assets and identifiable intangible assets acquired has been allocated to goodwill. The fair value assigned to identifiable intangible assets was determined primarily by using a discounted cash flow method.
	The Company's allocation of the purchase price for these acquisitions has been finalized. Changes in the purchase price allocation for CyberCoders from the Company’s previously filed Annual Report on Form 10-K for the year ended December 31, 2013 were primarily a $2.1 million reduction in estimated contingent consideration, a decrease in the value assigned to goodwill, an increase in the value assigned to identifiable intangible assets, and an increase in current and other liabilities. Measurement period adjustments resulting from the finalization of the purchase price allocation have been recorded retrospectively to the acquisition date.
	The following tables summarize (in thousands) the purchase price allocations for the acquisitions of Apex Systems and CyberCoders:
		2013 Acquisition				2012 Acquisition
		CyberCoders				Apex Systems
	Current assets	$	11,329			$	172,042
	Property and equipment	3,327				902
	Goodwill	69,018				264,590
	Identifiable intangible assets	37,860				251,555
	Other	915				494
	Total assets acquired	$	122,449			$	689,583
	Current liabilities	$	9,022			$	77,905
	Other	16,839				850
	Total liabilities assumed	25,861				78,755
	Total purchase price	$	96,588			$	610,828
	The following table summarizes (in thousands) the allocation of the purchase price among the identifiable intangible assets for the acquisitions of CyberCoders and Apex Systems:
				Identifiable Intangible Asset Value
				2013 Acquisition				2012 Acquisition
		Useful life		CyberCoders				Apex Systems
	Contractor relationships	2 - 5 years		$	4,000			$	10,589
	Customer relationships	2 - 10 years		860				92,147
	Non-compete agreements	3 - 7 years		800				2,076
	In-use software	6 years		18,900				—
	Trademark subject to amortization	2 years		—				—
	Trademarks	indefinite		13,300				146,743
	Total identifiable intangible assets acquired			$	37,860			$	251,555
	The summary below (in thousands, except for per share data) presents pro forma unaudited consolidated results of operations for 2013 and 2012 as if the acquisition of Apex Systems occurred on January 1, 2011, and the acquisition of CyberCoders occurred on January 1, 2012. The pro forma financial information gives effect to certain adjustments, including: amortization of intangible assets, interest expense on acquisition-related debt, provision for income taxes, changes in the management fees, and increased number of common shares as a result of the acquisition. Acquisition-related costs are assumed to have occurred at the beginning of the year prior to acquisition. The pro forma financial information is not necessarily indicative of the operating results that would have occurred if the acquisitions had been consummated as of the date indicated, nor are they necessarily indicative of future operating results.
			Year Ended December 31,
			2013				2012
		(unaudited)
	Revenues		$	1,582,699			$	1,363,225
	Income from continuing operations		$	54,947			$	49,022
	Net income		$	88,319			$	58,213
	Basic earnings per share:
	Income from continuing operations		$	1.03			$	0.94
	Net income		$	1.65			$	1.12
	Diluted earnings per share:
	Income from continuing operations		$	1.01			$	0.92
	Net income		$	1.62			$	1.09
	Weighted average number of shares outstanding		53,481				52,103
	Weighted average number of shares and dilutive shares outstanding		54,555				53,190
	On December 2, 2013, the Company acquired all of the outstanding partnership interests of Whitaker Medical, LLC ("Whitaker"), a provider of physician staffing services headquartered in Houston, Texas that was included in the Physician Segment, which was sold in February 2015 and its operating results are included in discontinued operations, see "Note 5. Discontinued Operations" for further information.

Discontinued_Operations_Discon

Discontinued Operations Discontinued Operations	12 Months Ended
	Dec. 31, 2014
Discontinued Operations [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	5. Discontinued Operations
	On February 12, 2013, the Company completed the sale of the Nurse Travel division for $33.7 million in cash and recognized a gain of $14.4 million, net of income taxes of $9.1 million. The Nurse Travel division, previously included in the Healthcare segment, has been presented as discontinued operations in our Consolidated Statements of Operations and Comprehensive Income for all periods presented.
	On December 2, 2013, the Company completed the sale of its Allied Healthcare division for $28.7 million in cash and recognized a gain of $16.4 million, net of income taxes of $10.4 million. The Allied Healthcare division, previously included in the Healthcare segment, has been presented as discontinued operations in our Consolidated Statements of Operations and Comprehensive Income for all periods presented.
	As of December 31, 2014, the Company closed its European retained search unit. Results for this European retained search unit, previously included in the Life Sciences Europe Segment, have been presented as discontinued operations in our Consolidated Statements of Operations and Comprehensive Income for all periods presented.
	On February 1, 2015 the Company completed the sale of its Physician Segment for $123.0 million, of which $6.0 million was placed in escrow for a period of 12 months. The gain on the sale was $25.7 million (net of income taxes of $14.4 million). The operating results of this segment are presented as discontinued operations in the consolidated statements of operations and comprehensive income for all periods presented. The consolidated balance sheets at December 31, 2014 and 2013 separately state the assets and liabilities of the Physician Segment as discontinued operations.
	The following table is a reconciliation of the major classes of assets and liabilities of the Physician Segment that are presented separately in the consolidated balance sheets at December 31, 2014 and December 31, 2013, to the previously reported balances:
		31-Dec-14
		As Previously Reported			Physician Segment			As Adjusted
	Cash and cash equivalents	$	31,714		$	(2,854	)	$	28,860
	Accounts receivable, net	298,761			(21,615		)	277,146
	Prepaid expenses and income taxes	14,513			(1,205		)	13,308
	Deferred income tax assets	19,067			(3,321		)	15,746
	Workers' compensation and medical malpractice receivable	18,728			(5,358		)	13,370
	Other current assets	3,121			—			3,121
	Current assets of discontinued operations	—			34,353			34,353
	Total current assets	385,904			—			385,904
	Property and equipment, net	46,819			(2,508		)	44,311
	Goodwill	570,697			(58,637		)	512,060
	Identifiable intangible assets, net	262,569			(11,960		)	250,609
	Other non-current assets	8,185			(568		)	7,617
	Non-current assets of discontinued operations	—			73,673			73,673
	Total assets	$	1,274,174		$	—		$	1,274,174
	Current portion of long-term debt	$	18,250		$	—		$	18,250
	Accounts payable	8,876			(951		)	7,925
	Accrued payroll and contract professional pay	87,189			(4,626		)	82,563
	Workers’ compensation and medical malpractice loss reserves	29,135			(13,571		)	15,564
	Income taxes payable	340			—			340
	Other current liabilities	21,776			(1,047		)	20,729
	Current liabilities of discontinued operations	—			20,195			20,195
	Total current liabilities	165,566			—			165,566
	Long-term debt	396,875			—			396,875
	Deferred income tax liabilities	67,909			(4,088		)	63,821
	Other long-term liabilities	9,416			(1,479		)	7,937
	Long-term liabilities of discontinued operations	—			5,567			5,567
	Total liabilities	$	639,766		$	—		$	639,766
		31-Dec-13
		As Previously Reported			Physician Segment			As Adjusted
	Cash and cash equivalents	$	37,350		$	(2,326	)	$	35,024
	Accounts receivable, net	262,200			(20,295		)	241,905
	Prepaid expenses and income taxes	8,686			(1,204		)	7,482
	Deferred income tax assets	17,530			(3,156		)	14,374
	Workers' compensation and medical malpractice receivable	21,200			(6,810		)	14,390
	Other current assets	3,471			(400		)	3,071
	Current assets of discontinued operations	—			34,191			34,191
	Total current assets	350,437			—			350,437
	Property and equipment, net	38,128			(2,080		)	36,048
	Goodwill	573,063			(58,637		)	514,426
	Identifiable intangible assets, net	287,855			(14,232		)	273,623
	Other non-current assets	9,326			(639		)	8,687
	Non-current assets of discontinued operations	—			75,588			75,588
	Total assets	$	1,258,809		$	—		$	1,258,809
	Current portion of long-term debt	$	10,000		$	—		$	10,000
	Accounts payable	8,370			(1,010		)	7,360
	Accrued payroll and contract professional pay	76,567			(4,321		)	72,246
	Workers’ compensation and medical malpractice loss reserves	32,751			(15,628		)	17,123
	Income taxes payable	13,120			—			13,120
	Other current liabilities	27,487			(1,027		)	26,460
	Current liabilities of discontinued operations	—			21,986			21,986
	Total current liabilities	168,295			—			168,295
	Long-term debt	389,813			—			389,813
	Deferred income tax liabilities	50,606			(3,817		)	46,789
	Other long-term liabilities	9,962			(1,365		)	8,597
	Long-term liabilities of discontinued operations	—			5,182			5,182
	Total liabilities	$	618,676		$	—		$	618,676
Cash flows from discontinued operations are included in the consolidated statements of cash flows for the years ended December 31, 2014, 2013 and 2012. The cash flows that are attributable to the Physician Segment are as follows:
	Year Ended
	December 31,
	2014			2013			2012
Net cash provided by (used in) operating activities	$	836		$	(108	)	$	123
Net cash used in investing activities	$	(308	)	$	(183	)	$	(574	)
The following is a summary of the operating results of all of the Company's discontinued operations (in thousands):
	Year Ended
	December 31,
	2014			2013			2012
Revenues	$	137,166		$	153,465		$	207,770
Cost of services	94,848			106,728			144,701
Gross profit	42,318			46,737			63,069
Selling, general and administrative expenses	33,078			38,991			42,334
Amortization of intangible assets	2,721			808			969
Operating income	6,519			6,938			19,766
Interest expense, net	—			(2,456		)	(4,415		)
Income before income taxes	6,519			4,482			15,351
Provision for income taxes	2,830			1,950			6,161
Income from discontinued operations	$	3,689		$	2,532		$	9,190

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt
	At December 31, 2014 and 2013, long-term debt consisted of the following (in thousands):
		2014			2013
	Senior Secured Debt:
	$125 million revolving credit facility, due May 2018	$	76,000		$	44,500
	Term A loan facility, due May 2018	158,813			92,500
	Term B loan facility, due May 2020	180,312			262,813
		$	415,125		$	399,813
	On May 16, 2013, the Company entered into a new $500.0 million credit facility and repaid all borrowings under the previous facility. This new facility initially consisted of (i) a $100.0 million, five-year term A loan facility, (ii) a $275.0 million seven-year term B loan facility and (iii) a $125.0 million, five-year revolving loan facility. On February 28, 2014, the Company increased the term A loan facility by $82.5 million and repaid $82.5 million on the term B loan facility. Under terms of the credit facility, the Company has the ability to increase the loan facilities for up to $100.0 million under certain specified conditions. During 2013, the Company expensed unamortized capitalized loan costs of $15.0 million related to the old borrowing facility.
	Borrowings under the term A loan facility and revolving loan facility bear interest at the Company's option, either the Eurodollar rate (LIBOR) or the base rate, plus 1.75% to 2.50%. Borrowings under the term B loan facility bear interest at the LIBOR rate, with a floor of 1.0%, plus 2.50%. The commitment fee on the undrawn portion available under the revolving loan facility ranges from 0.25% to 0.40% .
	At December 31, 2014, borrowings on the term A loan bore interest at 1.9%, borrowings on the term B loan bore interest at 3.5%, and the revolving loan facility bore interest of 0.17% base rate plus 2.0%. The weighted average interest rate at December 31, 2014 was 2.6%.
	During each of the next five years and thereafter, the Company will be required to make payments as follows (in thousands):
	2015		$	18,250
	2016		18,250
	2017		18,250
	2018		180,063
	2019		—
	Thereafter		180,312
	Total		$	415,125
	The Company is required to make mandatory prepayments of loans under the new facility, subject to specified exceptions, from excess cash flow and with the proceeds of asset sales, debt issuances and specified other events.
	The Company's obligations under the credit facility are guaranteed by substantially all of its direct and indirect domestic subsidiaries and secured by a lien on substantially all of the Company's tangible and intangible property and by a pledge of (i) all of the equity interests in its direct and indirect domestic subsidiaries and (ii) 65% of the equity interests in its first-tier foreign subsidiaries.
	The credit facility includes various restrictive covenants, including, the maximum ratio of consolidated funded debt to consolidated EBITDA (3.50:1.00 as of December 31, 2014, which steps down to 3.25:1.00 by June 30, 2015). There are also limits on the Company's and its subsidiaries' ability to incur liens, incur additional indebtedness, make loans and investments, engage in mergers and acquisitions, engage in asset sales, declare dividends or redeem or repurchase capital stock, alter the business conducted by the Company and its subsidiaries, transact with affiliates, prepay, redeem or purchase subordinated debt and amend or otherwise alter debt agreements. On January 30, 2015 the Company amended its credit facility to not require a mandatory prepayment from the sale of our Physician Segment (see "Note 5. Discontinued Operations" for further information).
	At December 31, 2014, the Company had $45.8 million of borrowing available under the revolving loan facility and was in compliance with all of its debt covenants.

Goodwill_and_Identifiable_Asse

Goodwill and Identifiable Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Identifiable Intangible Assets	Goodwill and Other Identifiable Intangible Assets
	During the quarter ended March 31, 2014, the Company underwent a realignment resulting in a change in the Company's reportable segments. The goodwill related to the former Life Sciences segment has been allocated to the respective segments below based upon the relative fair value of each component of the former Life Sciences segment. All prior periods have been retrospectively restated to conform to the current presentation (see "Note 14. Business Segments" for further information).
	The changes in the carrying amount of goodwill for the years ended December 31, 2014 and 2013 are as follows (in thousands):
		Apex				Oxford				Life Sciences Europe				Total
	Balance as of December 31, 2012
	Gross goodwill	$	289,712			$	150,619			$	3,753			$	444,084
	Accumulated impairment	—				—				—				—
		289,712				150,619				3,753				444,084
	CyberCoders Acquisition (see Note 4)	—				69,018				—				69,018
	Transfers	—				513				—				513
	Translation adjustment	—				—				811				811
	Balance as of December 31, 2013
	Gross goodwill	289,712				220,150				4,564				514,426
	Accumulated impairment	—				—				—				—
		289,712				220,150				4,564				514,426
	Translation adjustment	(1,761		)		(120		)		(485		)		(2,366		)
	Balance as of December 31, 2014
	Gross goodwill	287,951				220,030				4,079				512,060
	Accumulated impairment	—				—				—				—
		$	287,951			$	220,030			$	4,079			$	512,060
	As of December 31, 2014 and 2013, the Company had the following acquired intangible assets (in thousands):
					2014												2013
			Estimated Useful Life		Gross Carrying Amount				Accumulated Amortization				Net Carrying Amount				Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
	Subject to amortization:
	Customer relations		3 months – 10 years		$	101,141			$	53,434			$	47,707			$	101,697	$	38,930	$	62,767
	Contractor relations		2 - 7 years		39,332				32,021				7,311				39,384		28,321		11,063
	Non-compete agreements		2 - 7 years		3,654				1,922				1,732				3,743		1,362		2,381
	In-use software		6 years		18,900				3,366				15,534				18,900		263		18,637
					163,027				90,743				72,284				163,724		68,876		94,848
	Not subject to amortization:
	Trademarks				178,325				—				178,325				178,775		—		178,775
	Total				$	341,352			$	90,743			$	250,609			$	342,499	$	68,876	$	273,623
	Amortization expense for intangible assets with finite lives was $22.1 million in 2014, $20.9 million in 2013 and $17.0 million in 2012. Estimated amortization for each of the next five fiscal years and thereafter are as follows (in thousands):
	2015	$	19,381
	2016	16,366
	2017	12,078
	2018	9,669
	2019	7,972
	Thereafter	6,818
		$	72,284

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	The Company leases its facilities and certain office equipment under operating leases, which expire at various dates through 2023. Certain leases contain rent escalations and/or renewal options. Rent expense for all significant leases is recognized on a straight-line basis. The balance of the deferred rent liability reflected in other current liabilities in the accompanying Consolidated Balance Sheets was $0.3 million and $0.4 million at December 31, 2014 and 2013, respectively and the balance reflected in other long-term liabilities was $4.0 million and $3.4 million, at December 31, 2014 and 2013 respectively.
	The following is a summary of specified contractual cash obligation payments by the Company, excluding discontinued operations, as of December 31, 2014 (in thousands):
		Operating Leases		Related Party Leases		Total
	2015	$	15,012	$	1,066	$	16,078
	2016	12,809		1,190		13,999
	2017	9,871		1,169		11,040
	2018	8,015		1,302		9,317
	2019	5,796		1,282		7,078
	Thereafter	8,516		6,659		15,175
	Total	$	60,019	$	12,668	$	72,687
	Rent expense totaled $17.6 million for 2014, $15.4 million for 2013, and $11.4 million for 2012, and is included in SG&A expenses.
	As discussed in "Note 1. Summary of Significant Accounting Policies", the Company carries large retention policies for its workers’ compensation liability and its medical malpractice exposures. The workers' compensation and medical malpractice 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, differences in estimates, and actual payments for claims, are recognized in the period that the estimates changed or the payments were made. The workers' compensation and medical malpractice loss reserves were approximately $2.2 million and $2.7 million, net of anticipated insurance and indemnification recoveries of $13.4 million and $14.4 million, at December 31, 2014 and 2013, respectively. Additionally, the Company has unused stand-by letters of credit outstanding to secure obligations for workers’ compensation claims with various insurance carriers. The unused stand-by letters of credit at December 31, 2014 and December 31, 2013 were $3.2 million and $2.7 million, respectively.
	The Company is subject to contingent consideration agreements entered into in connection with certain of its acquisitions. If the acquired businesses meet predetermined targets, the Company is obligated to make additional cash payments in accordance with the terms of such contingent consideration agreements. As of December 31, 2014, the Company has potential future contingent consideration of $11.0 million through 2015.
	The Company has entered into various non-cancelable operating leases, primarily related to its facilities and certain office equipment used in the ordinary course of business. As a result of the Apex Systems acquisition, the Company leases two properties owned by related parties.
	At December 31, 2014 and 2013, the Company has an income tax reserve in other long-term liabilities related to uncertain tax positions of $0.9 million. Income tax reserves are not set forth in the table above. The Company is unable to make reasonably reliable estimates of the period of cash settlement since the statute of limitations might expire without examination by the respective tax authority.
	Certain employees participate in the Company’s Change in Control Severance Plan, or have separate agreements that provide for certain benefits in the event of termination following a change in control, as defined by the plan or agreement. Generally, these benefits are based on the employee’s length of service and position with the Company and include, severance, continuation of health insurance and in certain cases acceleration of vesting of option or stock awards.
	Legal Proceedings
	The Company is involved in various legal proceedings, claims and litigation arising in the ordinary course of business. Based on the facts currently available, the Company does not believe that the disposition of matters that are pending or asserted will have a material effect on its consolidated financial statements.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	The provision for income taxes consists of the following (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Current:
	Federal	$	28,581		$	26,284		$	15,201
	State	5,060			4,910			2,436
	Foreign	2,181			1,204			2,726
		35,822			32,398			20,363
	Deferred:
	Federal & State	15,991			4,244			6,358
	Foreign	(256		)	(84		)	(579		)
		15,735			4,160			5,779
		$	51,557		$	36,558		$	26,142
	Income from continuing operations before income taxes consists of the following (in thousands):
		Year Ended December 31,
		2014			2013			2012
	United States	$	122,496		$	82,970		$	56,450
	Foreign	2,556			4,728			3,155
		$	125,052		$	87,698		$	59,605
	The components of deferred tax assets (liabilities) are as follows (in thousands):
		December 31,			December 31,
		2014			2013
	Deferred income tax assets (liabilities):
	Current:
	Allowance for doubtful accounts	$	2,027		$	1,716
	Employee related accruals	7,240			6,442
	State taxes	473			555
	Workers’ compensation and medical malpractice loss reserves	4,068			4,767
	Other	5,259			4,050
		19,067			17,530
	Non-current:
	Intangibles	(59,226		)	(49,763		)
	Depreciation expense	(13,405		)	(6,574		)
	Stock-based compensation	3,022			3,761
	Net operating loss carryforwards	1,260			1,612
	Other	1,554			1,869
		(66,795		)	(49,095		)
	Valuation allowance	(1,114		)	(1,511		)
	Total non-current	(67,909		)	(50,606		)
	Total net deferred income tax liability	$	(48,842	)	$	(33,076	)
	The table above includes current deferred income tax assets of $3.3 million and $3.2 million for the Physician Segment as of December 31, 2014 and 2013, respectively, and non-current deferred income tax liabilities of $4.1 million and $3.8 million for the Physician Segment as of December 31, 2014 and 2013, respectively (see “Note 5. Discontinued Operations”).
	The reconciliation between the amount computed by applying the U.S. federal statutory tax rate of 35.0 percent to income before income taxes and the income tax provision is as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Income tax provision at the statutory rate	$	43,768		$	30,694		$	20,862
	State income taxes, net of federal benefit	4,674			3,807			2,357
	Disallowed meals and entertainment expenses	1,608			1,592			1,681
	Other	1,507			465			1,242
		$	51,557		$	36,558		$	26,142
	As of December 31, 2014, the Company had no federal net operating losses, state net operating losses of approximately $3.1 million and foreign net operating losses of approximately $6.3 million. The state net operating losses can be carried forward up to 20 years and begin expiring in 2015. The foreign net operating losses in the United Kingdom and Spain can be carried forward indefinitely. The Company has recorded a valuation allowance of approximately $1.0 million and $1.4 million at December 31, 2014 and December 31, 2013, respectively, related to net operating loss carryforwards.
	Basis differences in investments in foreign subsidiaries primarily related to undistributed earnings amounted to approximately $15.5 million at December 31, 2014. Those earnings are considered to be indefinitely reinvested; accordingly, no provision for U.S. federal and state income taxes has been provided thereon. Upon repatriation of those earnings, in the form of dividends or otherwise, the Company would be subject to both U.S. income taxes (subject to an adjustment for foreign tax credits) and withholding taxes payable to the various foreign countries. Determination of the amount of unrecognized deferred U.S. income tax liability is not practicable due to the complexities associated with its hypothetical calculation; however, unrecognized foreign tax credit carryforwards would be available to reduce some portion of the U.S. liability.
	The Company had gross deferred tax assets of $24.1 million and $23.9 million, and gross deferred tax liabilities of $71.4 million and $54.3 million, at December 31, 2014 and 2013, respectively. Management has determined the gross deferred tax assets are realizable, with the exception of foreign net operating losses discussed above.
	At December 31, 2014, 2013 and 2012, there were $0.8 million, $0.9 million and $0.3 million, respectively, of unrecognized tax benefits that if recognized would affect the annual effective tax rate. The gross unrecognized tax benefit is carried in other long-term liabilities. The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. The amount of interest and penalties recognized in the financial statements is not significant.
	The following is a reconciliation of the total amounts of unrecognized tax benefits (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Unrecognized Tax Benefit beginning of year	$	979		$	376		$	251
	Gross increases - tax positions in prior year	126			1,240			159
	Gross decreases - tax positions in prior year	—			(177		)	(34		)
	Lapse of the statute of limitations	(131		)	—			—
	Discontinued Operations	(126		)	(460		)	—
	Unrecognized Tax Benefit end of year	$	848		$	979		$	376
	The Company believes that there will be no significant increases or decreases to unrecognized tax benefits within the next 12 months. The Company is subject to taxation in the United States and various states and foreign jurisdictions. For U.S. federal income tax, the Company remains subject to examination for 2011 and subsequent years. For major U.S. states, with few exceptions, the Company remains subject to examination for 2010 and subsequent years. Generally, for the foreign countries, the Company remains subject to examination for 2010 and subsequent years.

Earnings_per_share

Earnings per share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings per share	Earnings per Share
	Basic earnings per share are computed based upon the weighted average number of shares outstanding and diluted earnings per share are computed based upon the weighted average number of shares and dilutive share equivalents (consisting of incentive stock options, non-qualified stock options, restricted stock units and employee stock purchase plan contributions) outstanding during the periods using the treasury stock method.
	The following is a reconciliation of the shares used to compute basic and diluted earnings per share (in thousands):
		Year Ended December 31,
		2014	2013	2012
	Weighted average number of common shares outstanding used to compute basic earnings per share	53,437	53,481	46,739
	Dilutive effect of stock-based awards	857	1,074	1,087
	Number of shares used to compute diluted earnings per share	54,294	54,555	47,826
	There were no significant share equivalents outstanding during the years ended December 31, 2014, 2013 and 2012 that were anti-dilutive when applying the treasury stock method.

Stockholders_Equity_Notes

Stockholders' Equity (Notes)	12 Months Ended
	Dec. 31, 2014
Equity, Class of Treasury Stock [Line Items]
Treasury Stock [Text Block]	11. Stockholders' Equity
	On July 21, 2014, the Board of Directors approved a program authorizing the Company to repurchase up to $100.0 million of the Company’s common stock. The authorization was effective August 4, 2014. During 2014, the Company repurchased 3.4 million shares of its common stock under this program at a cost of $100.0 million. All shares repurchased under this program were retired.  This resulted in a reduction of $31.2 million in paid-in capital, and a reduction of $68.8 million in retained earnings.
	On January 16, 2015 the Company’s Board of Directors approved a new $100.0 million share repurchase program (see "Note 16. Subsequent Events" for further information).

Stockbased_Compensation_Incent

Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan	Compensation: Stock-Based Compensation and 401(k) Retirement Savings Plan
	The Company believes that stock-based compensation better aligns the interests of its employees and directors with those of its stockholders versus exclusively providing cash-based compensation. Stock-based compensation provides incentives to retain and motivate executive officers and key employees responsible for driving Company performance and maintaining important relationships that contribute to the growth of the Company. The Company has issued restricted stock units ("RSUs"), stock options, and has awards that are accounted for as liabilities.
	Compensation expense related to stock-based compensation (which is included in SG&A expense in the accompanying Consolidated Statements of Operations and Comprehensive Income) was $16.2 million, $14.4 million, and $9.7 million for 2014, 2013 and 2012, respectively of which $15.6 million, $13.5 million, $9.1 million is included in SG&A expense and $0.6 million, $0.9 million, $0.6 million  is included in income from discontinued operations in the accompanying Consolidated Statements of Operations and Comprehensive Income for 2014, 2013 and 2012, respectively. The Company also recognized an income tax benefit for stock-based compensation arrangements of $4.7 million, $5.1 million, and $3.5 million in 2014, 2013 and 2012, respectively. As of December 31, 2014, there were 3,234,230 shares available for issuance under the Company's stock based compensation plans.
	Restricted Stock Units
	The fair value of each RSU is based on the fair market value of the awards on the grant date and the Company records compensation expense based on this value. Additionally, the Company analyzes historical vesting patterns for RSUs in order to estimate forfeiture rates. The forfeiture rate, set by management, is used to estimate the number of awards that will eventually vest and the associated impact on stock-based compensation expense.
	A summary of the status of the Company’s unvested RSUs as of December 31, 2014 and changes during the year then ended are presented below:
			Service Conditions			Performance and Service Conditions			Total			Weighted Average Grant-Date Fair Value Per Unit
	Unvested RSUs outstanding at December 31, 2013		972,364			394,874			1,367,238				$	18.9
	Granted		216,290			234,846			451,136				33.66
	Market value share count adjustment for liability awards		—			(12,826	)		(12,826	)			33.19
	Vested		(436,251	)		(230,837	)		(667,088	)			18.44
	Forfeited		(47,030	)		(4,869	)		(51,899	)			24.42
	Unvested RSUs outstanding at December 31, 2014		705,373			381,188			1,086,561				$	24.88
	Unvested and expected to vest RSUs outstanding at December 31, 2014		609,656			355,782			965,438				$	25.21
	The total number of shares vested in the table above includes 202,284 shares surrendered by the employees to the Company for payment of minimum tax withholding obligations. Shares of stock withheld for purposes of satisfying minimum tax withholding obligations are again available for issuance under the Plan.
	The weighted-average grant-date fair value of RSUs granted during the years ended December 31, 2014, 2013 and 2012 was $33.66, $26.17 and $16.01 per award, respectively. The total intrinsic value of RSUs vested during the years ended December 31, 2014, 2013 and 2012 was $21.3 million, $15.0 million and $13.7 million, respectively.
	As of December 31, 2014, there was unrecognized compensation expense of $14.9 million related to unvested RSUs based on awards that are expected to vest. The unrecognized compensation expense is expected to be recognized over a weighted-average period of 1.6 years.
	Liability Awards
	The Company classifies the following awards as a liability awards until the number of shares is determined, in accordance with the grant. The number of shares is determined by dividing the awards liability balance by the Company’s closing stock price on the settlement dates. The liability related to these awards was $1.5 million and $2.5 million at December 31, 2014 and 2013, respectively, and is included in other accrued expenses in the accompanying Consolidated Balance Sheets. Liability awards have a performance component and vest over one to three years. The performance goals are approved by the Compensation Committee of the Company’s Board of Directors.
	The following table summarizes the balance of liability awards and changes during the years ended December 31 2014, 2013 and 2012 (in thousands):
			2014				2013				2012
	Balances of liability awards at beginning of year		$	2,500			$	2,000			$	1,852
	Granted		500				1,000				1,694
	Settled		(1,497		)		(500		)		(1,546		)
	Canceled		(50		)		—				—
	Balance of liability awards end of year		$	1,453			$	2,500			$	2,000
	Expense related to liability awards during the years ended December 31, 2014, 2013 and 2012 was $0.5 million, $1.0 million, and $1.7 million, respectively. There was no unrecognized compensation expense for liability awards as of December 31, 2014.
	Stock Options
	The fair value of each option award is estimated on the date of grant using a Black-Scholes option valuation model that incorporates assumptions disclosed in the table below. Expected volatility is based on historical volatility of the underlying stock for a period consistent with the expected lives of the stock options as the Company believes this is a reasonable representation of future volatility. Additionally, the Company analyzes historical stock option exercise behavior in order to estimate employee turnover rates (i.e. forfeiture rates). The forfeiture rate, set by management, is used to estimate the number of options and awards that will eventually vest and the associated impact on stock-based compensation expense. The expected life, or term, of options granted is derived from historical exercise behavior and represents the period of time that stock option awards are expected to be outstanding. The Company has selected a risk-free rate based on the implied yield available on U.S. Treasury Securities with a maturity equivalent to the options’ expected term.
	The following table displays the weighted average assumptions that have been applied to estimate the fair value of stock option awards on the date of grant. During 2014 and 2013, the Company did not grant any stock option awards.
			Year Ended December 31,
				2012
	Dividend yield			—
	Risk-free interest rate			1.19	%
	Expected volatility			64.15	%
	Expected lives			7.3 years
	The following summarizes pricing and term information for options outstanding as of December 31, 2014:
											Options Outstanding							Options Exercisable
											Number Outstanding at			Weighted Average Remaining Contractual Life (years)	Weighted Average Exercise Price			Number Exercisable at	Weighted Average Exercise Price
	Range of Exercise Prices										31-Dec-14							31-Dec-14
	$	4.44			-		$	8.26			141,321			4.2		$	7.04	137,347		$	7.01
	9.19				-		11.39				231,836			3.2		11		198,891		11.09
	11.75				-		12.9				211,724			2.1		12.4		211,724		12.4
	13.31				-		13.58				35,000			2		13.32		34,531		13.32
	16.51				-		16.51				75,000			7.7		16.51		42,187		16.51
	$	4.44			-		$	16.51			694,881			3.5		$	11.33	624,680		$	11.13
	The following table is a summary of stock option activity during 2014.
			Incentive Stock Options		Non- Qualified Stock Options		Total		Weighted Average Exercise Price Per Share				Weighted Average Remaining Contractual			Aggregate Intrinsic Value
													Term (Years)
	Outstanding at December 31, 2013		69,416		790,529		859,945		$	10.61				4.8		$	20,903,000
	Exercised		-61,749		-85,414		-147,163		$	7.51
	Canceled		-3,400		-14,501		-17,901		$	8.25
	Outstanding at December 31, 2014		4,267		690,614		694,881		$	11.33				3.5		$	15,189,000
	Vested and Expected to Vest at December 31, 2014		4,267		686,970		691,237		$	11.32				3.5		$	15,120,000
	Exercisable at December 31, 2014		4,267		620,413		624,680		$	11.13				3.2		$	13,782,000
	There were no non-employee director stock options outstanding during the year ended December 31, 2014.
	The weighted-average grant-date fair value of options granted during the year ended December 31, 2012 was $10.34 per option. There were no options granted in 2014 and 2013. The total intrinsic value of options exercised during the years ended December 31, 2014, 2013 and 2012 was $3.9 million, $7.6 million, and $9.7 million.
	As of December 31, 2014 there was unrecognized compensation expense of $0.4 million related to unvested stock options based on options that are expected to vest. The unrecognized compensation expense is expected to be recognized over a weighted-average period of 1.4 years.
	Employee Stock Purchase Plan
	The On Assignment 2010 Employee Stock Purchase Plan ("ESPP") allows eligible employees to purchase common stock of the Company at a 15 percent discount to the market price as stipulated by the plan. Under the ESPP, 3,500,000 shares of common stock were reserved for issuance when it was approved on June 3, 2010 by the Company's stockholders. Shares of common stock are transferred to participating employees at the conclusion of each six-month enrollment period, which end on the last business day of the month in March and September each year. Compensation expense is measured using a Black-Scholes option-pricing model.
	The table below presents the average fair value per share, shares purchased, and the compensation expense that resulted from the two ESPP offering periods that took place in the years ended December 31, as indicated (expense in thousands):
	Year Ended December 31,			Average fair value per share			Shares		Expense
	2014			$8.35			207,805		$	1,756
	2013			$7.16			203,200		$	1,195
2012			$3.53			154,934		$	755
401(k) Retirement Savings Plan
The Company maintains various 401(k) retirement savings plans for the benefit of eligible employees. Under terms of these plans, eligible employees are able to make contributions to these plans on a tax-deferred basis and the Company may make matching or other contributions at its discretion. The Company made contributions to the 401(k) plans of $7.5 million, $6.0 million and $3.7 million for the years ended December 31, 2014, 2013 and 2012, respectively.

Business_Segments

Business Segments	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Business Segments	Business Segments
	The Company has three reportable segments: Apex, Oxford, and Life Sciences Europe.
	During the quarter ended March 31, 2014, the Company realigned its former Life Sciences Segment resulting in Lab Support U.S. now being included in the Apex Segment; Valesta U.S. now being included in the Oxford Segment; and the Life Sciences Europe Segment includes Lab Support Europe and Valesta Europe.
	On February 1, 2015 the Company sold the Physician Segment. During 2014 the Company discontinued the operations of its European retained search unit, formerly included in the Life Sciences Europe Segment. During 2013, the Company sold its Nurse Travel and Allied Healthcare division (see "Note 5. Discontinued Operations" for further information). The realignment and divestitures resulted in changes to the internal reporting package reviewed by the Chief Operating Decision Maker ("CODM"), and the Healthcare Segment no longer exists. Health Information Management, formerly included in the Healthcare Segment, is included in the Oxford Segment and unallocated corporate expenses are separately disclosed in order to align with the revised internal reporting package reviewed by the CODM. All prior periods have been retrospectively restated to conform to the current presentation.
	The Apex Segment provides information technology and scientific staffing professionals for contract, contract-to-hire and permanent placement positions to Fortune 1000 and mid-market clients across the United States, and offers consulting services for other select project-based needs. Apex Segment provides staffing and services support for companies from all major industries, including financial services, business services, consumer and industrials, technology, healthcare, government services, and communications.
	The Oxford Segment provides high-end contract and direct hire placement services of information technology and engineering professionals with expertise in specialized information technology, software and hardware engineering, and mechanical, electrical, validation and telecommunications engineering fields.
	The Life Sciences Europe Segment provides services of laboratory and scientific professionals to the biotechnology, pharmaceutical, food and beverage, medical device, personal care, chemical and environmental industries. These contract staffing specialties include chemists, clinical research associates, clinical lab assistants, engineers, biologists, biochemists, microbiologists, molecular biologists, food scientists, regulatory affairs specialists, lab assistants and other skilled scientific professionals.
	The Company’s management evaluates the performance of each segment primarily based on revenues, gross profit, and operating income. The information in the following table is derived directly from the segments’ internal financial reporting used for corporate management purposes. The Company's management does not evaluate, manage or measure performance of segments using asset information, and such information is not readily available. Accordingly, assets by reportable segment are not disclosed.
	The following tables present revenues, gross profit, operating income and amortization by reportable segment (in thousands):
		Year ended December 31, 2014
		Apex			Oxford			Life Sciences Europe			Corporate			Total
	Revenues	$	1,190,052		$	493,320		$	41,369		$	—		$	1,724,741
	Gross Profit	335,322			208,607			13,506			—			557,435
	Operating income	$	121,334		$	66,315		$	3,878		$	(53,745	)	137,782
	Amortization	16,356			5,491			274			9			22,130
		Year ended December 31, 2013
		Apex			Oxford			Life Sciences Europe			Corporate			Total
	Revenues	$	1,059,993		$	423,670		$	39,438		$	—		$	1,523,101
	Gross Profit	294,611			147,348			12,916			—			454,875
	Operating income	98,588			60,544			5,574			(48,119		)	116,587
	Amortization	19,524			965			364			90			20,943
		Year ended December 31, 2012
		Apex			Oxford			Life Sciences Europe			Corporate			Total
	Revenues	$	617,844		$	375,196		$	38,895		$	—		$	1,031,935
	Gross Profit	174,968			132,034			14,252			—			321,254
	Operating income	57,191			57,703			4,481			(46,362		)	73,013
	Amortization	15,665			437			654			291			17,047
	The Company operates internationally, with operations in the United States, Europe, Canada, Australia, and New Zealand. The following table represents revenues by geographic location (in thousands):
			Year Ended December 31,
			2014			2013			2012
	Revenues:
	Domestic		$	1,643,598		$	1,446,805		$	958,342
	Foreign		81,143			76,296			73,593
			$	1,724,741		$	1,523,101		$	1,031,935
	The following table represents long-lived assets by geographic location (in thousands):
			December 31,
			2014			2013			2012
	Long-lived Assets:
	Domestic		$	49,837		$	42,341		$	38,099
	Foreign		2,091			2,394			2,006
			$	51,928		$	44,735		$	40,105

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	The recorded values of cash and cash equivalents, accounts receivable, accounts payable and accrued expenses approximate their fair value based on their short-term nature. Long-term debt recorded in the Company’s Consolidated Balance Sheets at December 31, 2014 was $415.1 million. The fair value of the long-term debt was determined using the quoted price technique, based on Level 2 inputs including the yields of comparable companies with similar credit characteristics, was $414.8 million.
	The Company has obligations, to be paid in cash, to the former owners of CyberCoders, if certain future financial goals are met. The fair value of this contingent consideration is determined using an expected present value technique. Expected cash flows are determined using the probability - weighted average of possible outcomes that would occur should certain financial metrics be reached. There is no market data available to use in valuing the contingent consideration, therefore, the Company developed its own assumptions related to the future financial performance of the businesses to evaluate the fair value of these liabilities. As such, the contingent consideration is classified within Level 3. The liability for contingent consideration is established at the time of the acquisition and finalized by the end of the measurement period. At the end of each quarter, the fair value of this liability is re-measured and the change in the fair value (after the measurement period) is included in SG&A expenses.
	The assets and liabilities measured at fair value on a recurring basis are as follows (in thousands):
		As of December 31, 2014
		Fair Value Measurements Using									Total
		Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
		(Level 1)			(Level 2)			(Level 3)
	Contingent consideration to be paid in cash for the acquisitions	$	—		$	—		$	(3,000	)	$	(3,000	)
		As of December 31, 2013
		Fair Value Measurements Using									Total
		Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
		(Level 1)			(Level 2)			(Level 3)
	Contingent consideration to be paid in cash for the acquisitions	$	—		$	—		$	(3,667	)	$	(3,667	)
	Reconciliations of liabilities measured and carried at fair value on a recurring basis with the use of significant unobservable inputs (Level 3) are as follows (in thousands):
		Year Ended December 31,
		2014			2013
	Contingent consideration for acquisitions --
	Balance at beginning of year	$	(3,667	)	$	(6,737	)
	Additions for acquisitions	—			(3,000		)
	Payments on contingent consideration	691			3,425
	Fair value adjustments	—			2,744
	Foreign currency translation adjustment	(24		)	(99		)
	Balance at end of year	$	(3,000	)	$	(3,667	)
	Certain assets and liabilities, such as goodwill, are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (e.g., when there is evidence of impairment). For 2014 and 2013, no fair value adjustments were required for non-financial assets or liabilities.

Subsequent_Events_Notes

Subsequent Events (Notes)	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events
	The Company’s Board of Directors approved a $100.0 million share repurchase program on January 16, 2015. The authorization was effective February 23, 2015 and continues for two years thereafter.

Unaudited_Quarterly_Financial_

Unaudited Quarterly Financial Results	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Result	Unaudited Quarterly Results
	The following tables present unaudited quarterly financial information during the years ended December 31, 2014 and 2013. In the opinion of the Company’s management, the quarterly information contains all adjustments, consisting only of normal recurring accruals, necessary for a fair presentation thereof. The operating results for any quarter are not necessarily indicative of the results for any future periods.  The Company's Physician Segment, European retain search unit, and the Nurse Travel and Allied Healthcare divisions are reported as discontinued operations for all periods presented, see "Note 5. Discontinued Operations" for further information regarding the divestitures.
		2014
		Dec. 31,		Sept. 30,		June 30,		Mar. 31,
		(in thousands, except per share amounts)
	Revenues	$	441,023	$	442,443	$	434,424	$	406,851
	Gross profit	142,537		144,838		141,905		128,155
	Income from continuing operations	19,526		20,723		19,641		13,605
	Income from discontinued operations, net of income taxes	947		1,282		1,148		312
	Net income	$	20,473	$	22,005	$	20,789	$	13,917
	Basic earnings per common share:
	Continuing operations	$	0.38	$	0.39	$	0.36	$	0.25
	Discontinued operations	0.01		0.02		0.02		0.01
	Net income	$	0.39	$	0.41	$	0.38	$	0.26
	Diluted earnings per common share:
	Continuing operations	$	0.37	$	0.38	$	0.36	$	0.25
	Discontinued operations	0.02		0.03		0.02		—
	Net income	$	0.39	$	0.41	$	0.38	$	0.25
		2013
		Dec. 31,		Sept. 30,		June 30,		Mar. 31,
		(in thousands, except per share amounts)
	Revenues	$	396,070	$	394,400	$	380,779	$	351,852
	Gross profit	120,985		119,016		113,105		101,769
	Income from continuing operations	16,321		18,656		6,649		9,514
	Income from discontinued operations, net of income taxes	16,089		1,494		690		15,099
	Net income	$	32,410	$	20,150	$	7,339	$	24,613
	Basic earnings per common share:
	Continuing operations	$	0.3	$	0.35	$	0.12	$	0.18
	Discontinued operations	0.3		0.03		0.02		0.28
	Net income	$	0.6	$	0.38	$	0.14	$	0.46
	Diluted earnings per common share:
	Continuing operations	$	0.3	$	0.34	$	0.12	$	0.18
	Discontinued operations	0.29		0.03		0.02		0.28
	Net income	$	0.59	$	0.37	$	0.14	$	0.46

Schedule_II_Valuation_and_Qual

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2013
Valuation and Qualifying Accounts [Abstract]
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]
	Description	Balance at beginning of year		Provisions		Deductions from reserves		Balance at end of year
	Year ended December 31, 2014
	Allowance for doubtful accounts and billing adjustments	$	2,465	6,680		(4,741	)	$	4,404
	Workers’ compensation loss reserves	$	17,123	2,211		(3,770	)	$	15,564
	Year ended December 31, 2013
	Allowance for doubtful accounts and billing adjustments	$	3,395	1,474		(2,404	)	$	2,465
	Workers’ compensation loss reserves	$	17,037	5,850		(5,764	)	$	17,123
	Year ended December 31, 2012
	Allowance for doubtful accounts and billing adjustments	$	2,468	(446	)	1,373		$	3,395
	Workers’ compensation loss reserves	$	16,391	3,399		(2,753	)	$	17,037

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Notes)	12 Months Ended
	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Comprehensive Income (Loss) Note [Text Block]	12. Accumulated Other Comprehensive Income (Loss)
	The components of accumulated other comprehensive income (loss) were as follows (amounts in thousands):
		Foreign currency translation adjustment			Changes in fair value of derivative, net of tax			Accumulated other comprehensive income (loss)
	Balance at December 31, 2011	$	(1,658	)	$	(380	)	$	(2,038	)
	Other comprehensive income	854			(21		)	833
	Balance at December 31, 2012	(804		)	(401		)	(1,205		)
	Other comprehensive income	1,128			193			1,321
	Balance at December 31, 2013	324			(208		)	116
	Other comprehensive income	(4,772		)	86			(4,686		)
	Balance at December 31, 2014	$	(4,448	)	$	(122	)	$	(4,570	)

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Acquisition [Policy Text Block]	Assets and liabilities of the acquired companies were recorded at their estimated fair values at the dates of acquisition. The excess purchase price over the fair value of net tangible assets and identifiable intangible assets acquired has been allocated to goodwill. The fair value assigned to identifiable intangible assets was determined primarily by using a discounted cash flow method.
Principles of Consolidation	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	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	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. Conversion and direct hire fees are recognized when employment candidates begin permanent employment. The Company records a sales allowance against consolidated revenues, which is an estimate based on historical billing adjustment experience. The sales allowance is recorded as a reduction to revenues and an increase to the allowance for billing adjustments. The billing adjustment reserve includes an allowance for fallouts. Fallouts are direct hire and conversion fees 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 cost 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.
Income Tax	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 Transactions	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. Revenue 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 as a separate component of stockholders’ equity. Gains and losses resulting from foreign currency transactions, which are not material, are included in Selling, general and administrative (SG&A) expenses in the Consolidated Statements of Operations and Comprehensive Income.
Cash and Cash Equivalents	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	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. Receivables, or portions thereof, are written-off when deemed uncollectible.
Property and Equipment	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.
Goodwill and Identifiable Intangible Assets	Goodwill and Identifiable Intangible Assets. Goodwill and intangible assets with indefinite lives (consist entirely of trademarks) are tested for impairment on an annual basis as of October 31, and for goodwill whenever an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying amount and for indefinite lived intangibles, if events or changes in circumstances indicate that it is more likely than not that the asset is impaired.
	In order to test the trademarks for impairment, the Company determines the fair value of the trademarks and compares such amount to its carrying value. The fair value of the trademarks is determined using a projected discounted cash flow analysis based on the 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 value assumption. The royalty rate used in the analysis is based on transactions that have occurred in our industry. 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 relations are amortized using an accelerated method. Contractor relations and non-compete agreements are amortized using the straight-line method. Based upon the annual trademark impairment tests in 2014, 2013 and 2012, there were no trademark impairment charges.
	Goodwill is tested for impairment using a two-step process in which the first step compares the fair value of a reporting unit, which is generally an operating segment or one level below the operating segment level, which is a business and for which discrete financial information is available and reviewed by segment management, to the reporting unit's carrying value. The second step measures the amount of impairment by comparing the implied fair value of the respective reporting unit's goodwill with the carrying value of that goodwill. The goodwill impairment loss is measured by the amount the carrying value of goodwill exceeds the implied fair value of goodwill. Based upon the annual goodwill impairment tests in 2014, 2013 and 2012, there were no goodwill impairment charges.
Impairment or Disposal of Long-Lived Assets	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.
Workersb Compensation and Medical Malpractice Loss Reserves	Workers’ Compensation and Medical Malpractice Loss Reserves. The Company carries retention policies for its workers’ compensation liability and medical malpractice 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 and medical malpractice 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	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, workers’ compensation matters and medical malpractice insurance matters, requires the Company to use judgment.
Business Combinations	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.
Stock-based Compensation	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	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.
Fair Value of Financial Instruments	The recorded values of cash and cash equivalents, accounts receivable, accounts payable and accrued expenses approximate their fair value based on their short-term nature. Long-term debt recorded in the Company’s Consolidated Balance Sheets at December 31, 2014 was $415.1 million. The fair value of the long-term debt was determined using the quoted price technique, based on Level 2 inputs including the yields of comparable companies with similar credit characteristics, was $414.8 million.
Advertising Costs	Advertising Costs. Advertising costs, which are expensed as incurred, were $4.8 million in 2014, $4.0 million in 2013, and $3.3 million in 2012, and are included in selling, general and administrative ("SG&A") expenses.

Acquisitions_Business_Combinat

Acquisitions Business Combinations (Policies)	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisition [Policy Text Block]	Assets and liabilities of the acquired companies were recorded at their estimated fair values at the dates of acquisition. The excess purchase price over the fair value of net tangible assets and identifiable intangible assets acquired has been allocated to goodwill. The fair value assigned to identifiable intangible assets was determined primarily by using a discounted cash flow method.

Fair_Value_Measurements_Fair_V

Fair Value Measurements Fair Value of Financial Instruments Policy (Policies)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments, Policy [Policy Text Block]	The recorded values of cash and cash equivalents, accounts receivable, accounts payable and accrued expenses approximate their fair value based on their short-term nature. Long-term debt recorded in the Company’s Consolidated Balance Sheets at December 31, 2014 was $415.1 million. The fair value of the long-term debt was determined using the quoted price technique, based on Level 2 inputs including the yields of comparable companies with similar credit characteristics, was $414.8 million.

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment at December 31, 2014 and 2013 consisted of the following (in thousands):
		2014			2013
	Furniture, fixtures and equipment	$	10,957		$	7,486
	Computers and related equipment	21,741			11,358
	Computer software	41,416			35,943
	Leasehold improvements	5,637			4,711
	Work-in-progress	11,943			14,466
		91,694			73,964
	Less -- accumulated depreciation	(47,383		)	(37,916		)
		$	44,311		$	36,048

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Schedule of Purchase Price Allocation	The following tables summarize (in thousands) the purchase price allocations for the acquisitions of Apex Systems and CyberCoders:
		2013 Acquisition				2012 Acquisition
		CyberCoders				Apex Systems
	Current assets	$	11,329			$	172,042
	Property and equipment	3,327				902
	Goodwill	69,018				264,590
	Identifiable intangible assets	37,860				251,555
	Other	915				494
	Total assets acquired	$	122,449			$	689,583
	Current liabilities	$	9,022			$	77,905
	Other	16,839				850
	Total liabilities assumed	25,861				78,755
	Total purchase price	$	96,588			$	610,828
Schedule of Intangible Assets Acquired as Part of Business Combinations	The following table summarizes (in thousands) the allocation of the purchase price among the identifiable intangible assets for the acquisitions of CyberCoders and Apex Systems:
				Identifiable Intangible Asset Value
				2013 Acquisition				2012 Acquisition
		Useful life		CyberCoders				Apex Systems
	Contractor relationships	2 - 5 years		$	4,000			$	10,589
	Customer relationships	2 - 10 years		860				92,147
	Non-compete agreements	3 - 7 years		800				2,076
	In-use software	6 years		18,900				—
	Trademark subject to amortization	2 years		—				—
	Trademarks	indefinite		13,300				146,743
	Total identifiable intangible assets acquired			$	37,860			$	251,555
Schedule of Pro Forma Consolidated Results of Operations	The pro forma financial information is not necessarily indicative of the operating results that would have occurred if the acquisitions had been consummated as of the date indicated, nor are they necessarily indicative of future operating results.
			Year Ended December 31,
			2013				2012
		(unaudited)
	Revenues		$	1,582,699			$	1,363,225
	Income from continuing operations		$	54,947			$	49,022
	Net income		$	88,319			$	58,213
	Basic earnings per share:
	Income from continuing operations		$	1.03			$	0.94
	Net income		$	1.65			$	1.12
	Diluted earnings per share:
	Income from continuing operations		$	1.01			$	0.92
	Net income		$	1.62			$	1.09
	Weighted average number of shares outstanding		53,481				52,103
	Weighted average number of shares and dilutive shares outstanding		54,555				53,190

Discontinued_Operations_Discon1

Discontinued Operations Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2014
Discontinued Operations [Abstract]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	5. Discontinued Operations
	On February 12, 2013, the Company completed the sale of the Nurse Travel division for $33.7 million in cash and recognized a gain of $14.4 million, net of income taxes of $9.1 million. The Nurse Travel division, previously included in the Healthcare segment, has been presented as discontinued operations in our Consolidated Statements of Operations and Comprehensive Income for all periods presented.
	On December 2, 2013, the Company completed the sale of its Allied Healthcare division for $28.7 million in cash and recognized a gain of $16.4 million, net of income taxes of $10.4 million. The Allied Healthcare division, previously included in the Healthcare segment, has been presented as discontinued operations in our Consolidated Statements of Operations and Comprehensive Income for all periods presented.
	As of December 31, 2014, the Company closed its European retained search unit. Results for this European retained search unit, previously included in the Life Sciences Europe Segment, have been presented as discontinued operations in our Consolidated Statements of Operations and Comprehensive Income for all periods presented.
	On February 1, 2015 the Company completed the sale of its Physician Segment for $123.0 million, of which $6.0 million was placed in escrow for a period of 12 months. The gain on the sale was $25.7 million (net of income taxes of $14.4 million). The operating results of this segment are presented as discontinued operations in the consolidated statements of operations and comprehensive income for all periods presented. The consolidated balance sheets at December 31, 2014 and 2013 separately state the assets and liabilities of the Physician Segment as discontinued operations.
	The following table is a reconciliation of the major classes of assets and liabilities of the Physician Segment that are presented separately in the consolidated balance sheets at December 31, 2014 and December 31, 2013, to the previously reported balances:
		31-Dec-14
		As Previously Reported			Physician Segment			As Adjusted
	Cash and cash equivalents	$	31,714		$	(2,854	)	$	28,860
	Accounts receivable, net	298,761			(21,615		)	277,146
	Prepaid expenses and income taxes	14,513			(1,205		)	13,308
	Deferred income tax assets	19,067			(3,321		)	15,746
	Workers' compensation and medical malpractice receivable	18,728			(5,358		)	13,370
	Other current assets	3,121			—			3,121
	Current assets of discontinued operations	—			34,353			34,353
	Total current assets	385,904			—			385,904
	Property and equipment, net	46,819			(2,508		)	44,311
	Goodwill	570,697			(58,637		)	512,060
	Identifiable intangible assets, net	262,569			(11,960		)	250,609
	Other non-current assets	8,185			(568		)	7,617
	Non-current assets of discontinued operations	—			73,673			73,673
	Total assets	$	1,274,174		$	—		$	1,274,174
	Current portion of long-term debt	$	18,250		$	—		$	18,250
	Accounts payable	8,876			(951		)	7,925
	Accrued payroll and contract professional pay	87,189			(4,626		)	82,563
	Workers’ compensation and medical malpractice loss reserves	29,135			(13,571		)	15,564
	Income taxes payable	340			—			340
	Other current liabilities	21,776			(1,047		)	20,729
	Current liabilities of discontinued operations	—			20,195			20,195
	Total current liabilities	165,566			—			165,566
	Long-term debt	396,875			—			396,875
	Deferred income tax liabilities	67,909			(4,088		)	63,821
	Other long-term liabilities	9,416			(1,479		)	7,937
	Long-term liabilities of discontinued operations	—			5,567			5,567
	Total liabilities	$	639,766		$	—		$	639,766
		31-Dec-13
		As Previously Reported			Physician Segment			As Adjusted
	Cash and cash equivalents	$	37,350		$	(2,326	)	$	35,024
	Accounts receivable, net	262,200			(20,295		)	241,905
	Prepaid expenses and income taxes	8,686			(1,204		)	7,482
	Deferred income tax assets	17,530			(3,156		)	14,374
	Workers' compensation and medical malpractice receivable	21,200			(6,810		)	14,390
	Other current assets	3,471			(400		)	3,071
	Current assets of discontinued operations	—			34,191			34,191
	Total current assets	350,437			—			350,437
	Property and equipment, net	38,128			(2,080		)	36,048
	Goodwill	573,063			(58,637		)	514,426
	Identifiable intangible assets, net	287,855			(14,232		)	273,623
	Other non-current assets	9,326			(639		)	8,687
	Non-current assets of discontinued operations	—			75,588			75,588
	Total assets	$	1,258,809		$	—		$	1,258,809
	Current portion of long-term debt	$	10,000		$	—		$	10,000
	Accounts payable	8,370			(1,010		)	7,360
	Accrued payroll and contract professional pay	76,567			(4,321		)	72,246
	Workers’ compensation and medical malpractice loss reserves	32,751			(15,628		)	17,123
	Income taxes payable	13,120			—			13,120
	Other current liabilities	27,487			(1,027		)	26,460
	Current liabilities of discontinued operations	—			21,986			21,986
	Total current liabilities	168,295			—			168,295
	Long-term debt	389,813			—			389,813
	Deferred income tax liabilities	50,606			(3,817		)	46,789
	Other long-term liabilities	9,962			(1,365		)	8,597
	Long-term liabilities of discontinued operations	—			5,182			5,182
	Total liabilities	$	618,676		$	—		$	618,676
Cash flows from discontinued operations are included in the consolidated statements of cash flows for the years ended December 31, 2014, 2013 and 2012. The cash flows that are attributable to the Physician Segment are as follows:
	Year Ended
	December 31,
	2014			2013			2012
Net cash provided by (used in) operating activities	$	836		$	(108	)	$	123
Net cash used in investing activities	$	(308	)	$	(183	)	$	(574	)
The following is a summary of the operating results of all of the Company's discontinued operations (in thousands):
	Year Ended
	December 31,
	2014			2013			2012
Revenues	$	137,166		$	153,465		$	207,770
Cost of services	94,848			106,728			144,701
Gross profit	42,318			46,737			63,069
Selling, general and administrative expenses	33,078			38,991			42,334
Amortization of intangible assets	2,721			808			969
Operating income	6,519			6,938			19,766
Interest expense, net	—			(2,456		)	(4,415		)
Income before income taxes	6,519			4,482			15,351
Provision for income taxes	2,830			1,950			6,161
Income from discontinued operations	$	3,689		$	2,532		$	9,190
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]	The following table is a reconciliation of the major classes of assets and liabilities of the Physician Segment that are presented separately in the consolidated balance sheets at December 31, 2014 and December 31, 2013, to the previously reported balances:
		31-Dec-14
		As Previously Reported			Physician Segment			As Adjusted
	Cash and cash equivalents	$	31,714		$	(2,854	)	$	28,860
	Accounts receivable, net	298,761			(21,615		)	277,146
	Prepaid expenses and income taxes	14,513			(1,205		)	13,308
	Deferred income tax assets	19,067			(3,321		)	15,746
	Workers' compensation and medical malpractice receivable	18,728			(5,358		)	13,370
	Other current assets	3,121			—			3,121
	Current assets of discontinued operations	—			34,353			34,353
	Total current assets	385,904			—			385,904
	Property and equipment, net	46,819			(2,508		)	44,311
	Goodwill	570,697			(58,637		)	512,060
	Identifiable intangible assets, net	262,569			(11,960		)	250,609
	Other non-current assets	8,185			(568		)	7,617
	Non-current assets of discontinued operations	—			73,673			73,673
	Total assets	$	1,274,174		$	—		$	1,274,174
	Current portion of long-term debt	$	18,250		$	—		$	18,250
	Accounts payable	8,876			(951		)	7,925
	Accrued payroll and contract professional pay	87,189			(4,626		)	82,563
	Workers’ compensation and medical malpractice loss reserves	29,135			(13,571		)	15,564
	Income taxes payable	340			—			340
	Other current liabilities	21,776			(1,047		)	20,729
	Current liabilities of discontinued operations	—			20,195			20,195
	Total current liabilities	165,566			—			165,566
	Long-term debt	396,875			—			396,875
	Deferred income tax liabilities	67,909			(4,088		)	63,821
	Other long-term liabilities	9,416			(1,479		)	7,937
	Long-term liabilities of discontinued operations	—			5,567			5,567
	Total liabilities	$	639,766		$	—		$	639,766
		31-Dec-13
		As Previously Reported			Physician Segment			As Adjusted
	Cash and cash equivalents	$	37,350		$	(2,326	)	$	35,024
	Accounts receivable, net	262,200			(20,295		)	241,905
	Prepaid expenses and income taxes	8,686			(1,204		)	7,482
	Deferred income tax assets	17,530			(3,156		)	14,374
	Workers' compensation and medical malpractice receivable	21,200			(6,810		)	14,390
	Other current assets	3,471			(400		)	3,071
	Current assets of discontinued operations	—			34,191			34,191
	Total current assets	350,437			—			350,437
	Property and equipment, net	38,128			(2,080		)	36,048
	Goodwill	573,063			(58,637		)	514,426
	Identifiable intangible assets, net	287,855			(14,232		)	273,623
	Other non-current assets	9,326			(639		)	8,687
	Non-current assets of discontinued operations	—			75,588			75,588
	Total assets	$	1,258,809		$	—		$	1,258,809
	Current portion of long-term debt	$	10,000		$	—		$	10,000
	Accounts payable	8,370			(1,010		)	7,360
	Accrued payroll and contract professional pay	76,567			(4,321		)	72,246
	Workers’ compensation and medical malpractice loss reserves	32,751			(15,628		)	17,123
	Income taxes payable	13,120			—			13,120
	Other current liabilities	27,487			(1,027		)	26,460
	Current liabilities of discontinued operations	—			21,986			21,986
	Total current liabilities	168,295			—			168,295
	Long-term debt	389,813			—			389,813
	Deferred income tax liabilities	50,606			(3,817		)	46,789
	Other long-term liabilities	9,962			(1,365		)	8,597
	Long-term liabilities of discontinued operations	—			5,182			5,182
	Total liabilities	$	618,676		$	—		$	618,676
		Year Ended
		December 31,
		2014			2013			2012
	Revenues	$	137,166		$	153,465		$	207,770
	Cost of services	94,848			106,728			144,701
Gross profit	42,318			46,737			63,069
Selling, general and administrative expenses	33,078			38,991			42,334
Amortization of intangible assets	2,721			808			969
Operating income	6,519			6,938			19,766
Interest expense, net	—			(2,456		)	(4,415		)
Income before income taxes	6,519			4,482			15,351
Provision for income taxes	2,830			1,950			6,161
Income from discontinued operations	$	3,689		$	2,532		$	9,190
The cash flows that are attributable to the Physician Segment are as follows:
	Year Ended
	December 31,
	2014			2013			2012
Net cash provided by (used in) operating activities	$	836		$	(108	)	$	123
Net cash used in investing activities	$	(308	)	$	(183	)	$	(574	)

LongTerm_Debt_Tables

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Contractual Obligation, Fiscal Year Maturity Schedule [Table Text Block]	During each of the next five years and thereafter, the Company will be required to make payments as follows (in thousands):
	2015		$	18,250
	2016		18,250
	2017		18,250
	2018		180,063
	2019		—
	Thereafter		180,312
	Total		$	415,125
	The following is a summary of specified contractual cash obligation payments by the Company, excluding discontinued operations, as of December 31, 2014 (in thousands):
			Operating Leases			Related Party Leases		Total
	2015		$	15,012		$	1,066	$	16,078
	2016		12,809			1,190		13,999
	2017		9,871			1,169		11,040
	2018		8,015			1,302		9,317
	2019		5,796			1,282		7,078
	Thereafter		8,516			6,659		15,175
	Total		$	60,019		$	12,668	$	72,687
Schedule of Long-term Debt	ong-term debt consisted of the following (in thousands):
		2014			2013
	Senior Secured Debt:
	$125 million revolving credit facility, due May 2018	$	76,000		$	44,500
	Term A loan facility, due May 2018	158,813			92,500
	Term B loan facility, due May 2020	180,312			262,813
		$	415,125		$	399,813

Goodwill_and_Identifiable_Asse1

Goodwill and Identifiable Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill
	The changes in the carrying amount of goodwill for the years ended December 31, 2014 and 2013 are as follows (in thousands):
		Apex				Oxford				Life Sciences Europe				Total
	Balance as of December 31, 2012
	Gross goodwill	$	289,712			$	150,619			$	3,753			$	444,084
	Accumulated impairment	—				—				—				—
		289,712				150,619				3,753				444,084
	CyberCoders Acquisition (see Note 4)	—				69,018				—				69,018
	Transfers	—				513				—				513
	Translation adjustment	—				—				811				811
	Balance as of December 31, 2013
	Gross goodwill	289,712				220,150				4,564				514,426
	Accumulated impairment	—				—				—				—
		289,712				220,150				4,564				514,426
	Translation adjustment	(1,761		)		(120		)		(485		)		(2,366		)
	Balance as of December 31, 2014
	Gross goodwill	287,951				220,030				4,079				512,060
	Accumulated impairment	—				—				—				—
		$	287,951			$	220,030			$	4,079			$	512,060
Schedule of Acquired Intangible Assets	As of December 31, 2014 and 2013, the Company had the following acquired intangible assets (in thousands):
					2014												2013
			Estimated Useful Life		Gross Carrying Amount				Accumulated Amortization				Net Carrying Amount				Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount
	Subject to amortization:
	Customer relations		3 months – 10 years		$	101,141			$	53,434			$	47,707			$	101,697	$	38,930	$	62,767
	Contractor relations		2 - 7 years		39,332				32,021				7,311				39,384		28,321		11,063
	Non-compete agreements		2 - 7 years		3,654				1,922				1,732				3,743		1,362		2,381
	In-use software		6 years		18,900				3,366				15,534				18,900		263		18,637
					163,027				90,743				72,284				163,724		68,876		94,848
	Not subject to amortization:
	Trademarks				178,325				—				178,325				178,775		—		178,775
	Total				$	341,352			$	90,743			$	250,609			$	342,499	$	68,876	$	273,623
Schedule of Estimated Future Amortization Expense	Estimated amortization for each of the next five fiscal years and thereafter are as follows (in thousands):
	2015	$	19,381
	2016	16,366
	2017	12,078
	2018	9,669
	2019	7,972
	Thereafter	6,818
		$	72,284

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of Contractual Cash Obligation Payments	During each of the next five years and thereafter, the Company will be required to make payments as follows (in thousands):
	2015	$	18,250
	2016	18,250
	2017	18,250
	2018	180,063
	2019	—
	Thereafter	180,312
	Total	$	415,125
	The following is a summary of specified contractual cash obligation payments by the Company, excluding discontinued operations, as of December 31, 2014 (in thousands):
		Operating Leases		Related Party Leases		Total
	2015	$	15,012	$	1,066	$	16,078
	2016	12,809		1,190		13,999
	2017	9,871		1,169		11,040
	2018	8,015		1,302		9,317
	2019	5,796		1,282		7,078
	Thereafter	8,516		6,659		15,175
	Total	$	60,019	$	12,668	$	72,687

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Components of Income Taxes	The provision for income taxes consists of the following (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Current:
	Federal	$	28,581		$	26,284		$	15,201
	State	5,060			4,910			2,436
	Foreign	2,181			1,204			2,726
		35,822			32,398			20,363
	Deferred:
	Federal & State	15,991			4,244			6,358
	Foreign	(256		)	(84		)	(579		)
		15,735			4,160			5,779
		$	51,557		$	36,558		$	26,142
Income (Loss) before Income Tax Provision	Income from continuing operations before income taxes consists of the following (in thousands):
		Year Ended December 31,
		2014			2013			2012
	United States	$	122,496		$	82,970		$	56,450
	Foreign	2,556			4,728			3,155
		$	125,052		$	87,698		$	59,605
Schedule of Deferred Tax Assets and Liabilities	The components of deferred tax assets (liabilities) are as follows (in thousands):
		December 31,			December 31,
		2014			2013
	Deferred income tax assets (liabilities):
	Current:
	Allowance for doubtful accounts	$	2,027		$	1,716
	Employee related accruals	7,240			6,442
	State taxes	473			555
	Workers’ compensation and medical malpractice loss reserves	4,068			4,767
	Other	5,259			4,050
		19,067			17,530
	Non-current:
	Intangibles	(59,226		)	(49,763		)
	Depreciation expense	(13,405		)	(6,574		)
	Stock-based compensation	3,022			3,761
	Net operating loss carryforwards	1,260			1,612
	Other	1,554			1,869
		(66,795		)	(49,095		)
	Valuation allowance	(1,114		)	(1,511		)
	Total non-current	(67,909		)	(50,606		)
	Total net deferred income tax liability	$	(48,842	)	$	(33,076	)
Schedule of Effective Income Tax Rate Reconciliation	The reconciliation between the amount computed by applying the U.S. federal statutory tax rate of 35.0 percent to income before income taxes and the income tax provision is as follows (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Income tax provision at the statutory rate	$	43,768		$	30,694		$	20,862
	State income taxes, net of federal benefit	4,674			3,807			2,357
	Disallowed meals and entertainment expenses	1,608			1,592			1,681
	Other	1,507			465			1,242
		$	51,557		$	36,558		$	26,142
Schedule of Unrecognized Tax Benefits Roll Forward	The following is a reconciliation of the total amounts of unrecognized tax benefits (in thousands):
		Year Ended December 31,
		2014			2013			2012
	Unrecognized Tax Benefit beginning of year	$	979		$	376		$	251
	Gross increases - tax positions in prior year	126			1,240			159
	Gross decreases - tax positions in prior year	—			(177		)	(34		)
	Lapse of the statute of limitations	(131		)	—			—
	Discontinued Operations	(126		)	(460		)	—
	Unrecognized Tax Benefit end of year	$	848		$	979		$	376

Earnings_per_share_Tables

Earnings per share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Reconciliation of Shares Used to Compute Basic and Diluted Earnings per Share	The following is a reconciliation of the shares used to compute basic and diluted earnings per share (in thousands):
		Year Ended December 31,
		2014	2013	2012
	Weighted average number of common shares outstanding used to compute basic earnings per share	53,437	53,481	46,739
	Dilutive effect of stock-based awards	857	1,074	1,087
	Number of shares used to compute diluted earnings per share	54,294	54,555	47,826

Stockbased_Compensation_Incent1

Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]	The table below presents the average fair value per share, shares purchased, and the compensation expense that resulted from the two ESPP offering periods that took place in the years ended December 31, as indicated (expense in thousands):
	Year Ended December 31,			Average fair value per share			Shares		Expense
	2014			$8.35			207,805		$	1,756
	2013			$7.16			203,200		$	1,195
	2012			$3.53			154,934		$	755
Schedule of Other Share-based Compensation, Activity [Table Text Block]	The following table summarizes the balance of liability awards and changes during the years ended December 31 2014, 2013 and 2012 (in thousands):
			2014				2013				2012
	Balances of liability awards at beginning of year		$	2,500			$	2,000			$	1,852
	Granted		500				1,000				1,694
	Settled		(1,497		)		(500		)		(1,546		)
	Canceled		(50		)		—				—
	Balance of liability awards end of year		$	1,453			$	2,500			$	2,000
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The following table displays the weighted average assumptions that have been applied to estimate the fair value of stock option awards on the date of grant. During 2014 and 2013, the Company did not grant any stock option awards.
			Year Ended December 31,
				2012
	Dividend yield			—
	Risk-free interest rate			1.19	%
	Expected volatility			64.15	%
	Expected lives			7.3 years
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	The following summarizes pricing and term information for options outstanding as of December 31, 2014:
											Options Outstanding							Options Exercisable
											Number Outstanding at			Weighted Average Remaining Contractual Life (years)	Weighted Average Exercise Price			Number Exercisable at	Weighted Average Exercise Price
	Range of Exercise Prices										31-Dec-14							31-Dec-14
	$	4.44			-		$	8.26			141,321			4.2		$	7.04	137,347		$	7.01
	9.19				-		11.39				231,836			3.2		11		198,891		11.09
	11.75				-		12.9				211,724			2.1		12.4		211,724		12.4
	13.31				-		13.58				35,000			2		13.32		34,531		13.32
	16.51				-		16.51				75,000			7.7		16.51		42,187		16.51
	$	4.44			-		$	16.51			694,881			3.5		$	11.33	624,680		$	11.13
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	The following table is a summary of stock option activity during 2014.
			Incentive Stock Options		Non- Qualified Stock Options		Total		Weighted Average Exercise Price Per Share				Weighted Average Remaining Contractual			Aggregate Intrinsic Value
													Term (Years)
	Outstanding at December 31, 2013		69,416		790,529		859,945		$	10.61				4.8		$	20,903,000
	Exercised		-61,749		-85,414		-147,163		$	7.51
	Canceled		-3,400		-14,501		-17,901		$	8.25
	Outstanding at December 31, 2014		4,267		690,614		694,881		$	11.33				3.5		$	15,189,000
	Vested and Expected to Vest at December 31, 2014		4,267		686,970		691,237		$	11.32				3.5		$	15,120,000
	Exercisable at December 31, 2014		4,267		620,413		624,680		$	11.13				3.2		$	13,782,000
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	A summary of the status of the Company’s unvested RSUs as of December 31, 2014 and changes during the year then ended are presented below:
			Service Conditions			Performance and Service Conditions			Total			Weighted Average Grant-Date Fair Value Per Unit
	Unvested RSUs outstanding at December 31, 2013		972,364			394,874			1,367,238				$	18.9
	Granted		216,290			234,846			451,136				33.66
	Market value share count adjustment for liability awards		—			(12,826	)		(12,826	)			33.19
	Vested		(436,251	)		(230,837	)		(667,088	)			18.44
	Forfeited		(47,030	)		(4,869	)		(51,899	)			24.42
	Unvested RSUs outstanding at December 31, 2014		705,373			381,188			1,086,561				$	24.88
	Unvested and expected to vest RSUs outstanding at December 31, 2014		609,656			355,782			965,438				$	25.21

Business_Segments_Tables

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment
		Year ended December 31, 2014
		Apex			Oxford			Life Sciences Europe			Corporate			Total
	Revenues	$	1,190,052		$	493,320		$	41,369		$	—		$	1,724,741
	Gross Profit	335,322			208,607			13,506			—			557,435
	Operating income	$	121,334		$	66,315		$	3,878		$	(53,745	)	137,782
	Amortization	16,356			5,491			274			9			22,130
		Year ended December 31, 2013
		Apex			Oxford			Life Sciences Europe			Corporate			Total
	Revenues	$	1,059,993		$	423,670		$	39,438		$	—		$	1,523,101
	Gross Profit	294,611			147,348			12,916			—			454,875
	Operating income	98,588			60,544			5,574			(48,119		)	116,587
	Amortization	19,524			965			364			90			20,943
		Year ended December 31, 2012
		Apex			Oxford			Life Sciences Europe			Corporate			Total
	Revenues	$	617,844		$	375,196		$	38,895		$	—		$	1,031,935
	Gross Profit	174,968			132,034			14,252			—			321,254
	Operating income	57,191			57,703			4,481			(46,362		)	73,013
	Amortization	15,665			437			654			291			17,047
Disclosure on Geographic Areas, Description of Revenue from External Customers	The Company operates internationally, with operations in the United States, Europe, Canada, Australia, and New Zealand. The following table represents revenues by geographic location (in thousands):
			Year Ended December 31,
			2014			2013			2012
	Revenues:
	Domestic		$	1,643,598		$	1,446,805		$	958,342
	Foreign		81,143			76,296			73,593
			$	1,724,741		$	1,523,101		$	1,031,935
Schedule of Revenue by Geographical Areas	Business Segments
	The Company has three reportable segments: Apex, Oxford, and Life Sciences Europe.
	During the quarter ended March 31, 2014, the Company realigned its former Life Sciences Segment resulting in Lab Support U.S. now being included in the Apex Segment; Valesta U.S. now being included in the Oxford Segment; and the Life Sciences Europe Segment includes Lab Support Europe and Valesta Europe.
	On February 1, 2015 the Company sold the Physician Segment. During 2014 the Company discontinued the operations of its European retained search unit, formerly included in the Life Sciences Europe Segment. During 2013, the Company sold its Nurse Travel and Allied Healthcare division (see "Note 5. Discontinued Operations" for further information). The realignment and divestitures resulted in changes to the internal reporting package reviewed by the Chief Operating Decision Maker ("CODM"), and the Healthcare Segment no longer exists. Health Information Management, formerly included in the Healthcare Segment, is included in the Oxford Segment and unallocated corporate expenses are separately disclosed in order to align with the revised internal reporting package reviewed by the CODM. All prior periods have been retrospectively restated to conform to the current presentation.
	The Apex Segment provides information technology and scientific staffing professionals for contract, contract-to-hire and permanent placement positions to Fortune 1000 and mid-market clients across the United States, and offers consulting services for other select project-based needs. Apex Segment provides staffing and services support for companies from all major industries, including financial services, business services, consumer and industrials, technology, healthcare, government services, and communications.
	The Oxford Segment provides high-end contract and direct hire placement services of information technology and engineering professionals with expertise in specialized information technology, software and hardware engineering, and mechanical, electrical, validation and telecommunications engineering fields.
	The Life Sciences Europe Segment provides services of laboratory and scientific professionals to the biotechnology, pharmaceutical, food and beverage, medical device, personal care, chemical and environmental industries. These contract staffing specialties include chemists, clinical research associates, clinical lab assistants, engineers, biologists, biochemists, microbiologists, molecular biologists, food scientists, regulatory affairs specialists, lab assistants and other skilled scientific professionals.
	The Company’s management evaluates the performance of each segment primarily based on revenues, gross profit, and operating income. The information in the following table is derived directly from the segments’ internal financial reporting used for corporate management purposes. The Company's management does not evaluate, manage or measure performance of segments using asset information, and such information is not readily available. Accordingly, assets by reportable segment are not disclosed.
	The following tables present revenues, gross profit, operating income and amortization by reportable segment (in thousands):
		Year ended December 31, 2014
		Apex			Oxford			Life Sciences Europe			Corporate			Total
	Revenues	$	1,190,052		$	493,320		$	41,369		$	—		$	1,724,741
	Gross Profit	335,322			208,607			13,506			—			557,435
	Operating income	$	121,334		$	66,315		$	3,878		$	(53,745	)	137,782
	Amortization	16,356			5,491			274			9			22,130
		Year ended December 31, 2013
		Apex			Oxford			Life Sciences Europe			Corporate			Total
	Revenues	$	1,059,993		$	423,670		$	39,438		$	—		$	1,523,101
	Gross Profit	294,611			147,348			12,916			—			454,875
	Operating income	98,588			60,544			5,574			(48,119		)	116,587
	Amortization	19,524			965			364			90			20,943
		Year ended December 31, 2012
		Apex			Oxford			Life Sciences Europe			Corporate			Total
	Revenues	$	617,844		$	375,196		$	38,895		$	—		$	1,031,935
	Gross Profit	174,968			132,034			14,252			—			321,254
	Operating income	57,191			57,703			4,481			(46,362		)	73,013
	Amortization	15,665			437			654			291			17,047
	The Company operates internationally, with operations in the United States, Europe, Canada, Australia, and New Zealand. The following table represents revenues by geographic location (in thousands):
			Year Ended December 31,
			2014			2013			2012
	Revenues:
	Domestic		$	1,643,598		$	1,446,805		$	958,342
	Foreign		81,143			76,296			73,593
			$	1,724,741		$	1,523,101		$	1,031,935
	The following table represents long-lived assets by geographic location (in thousands):
			December 31,
			2014			2013			2012
	Long-lived Assets:
	Domestic		$	49,837		$	42,341		$	38,099
	Foreign		2,091			2,394			2,006
			$	51,928		$	44,735		$	40,105
Long Lived Assets By Geographic Location Domestic And Foreign	The following table represents long-lived assets by geographic location (in thousands):
			December 31,
			2014			2013			2012
	Long-lived Assets:
	Domestic		$	49,837		$	42,341		$	38,099
	Foreign		2,091			2,394			2,006
			$	51,928		$	44,735		$	40,105

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The assets and liabilities measured at fair value on a recurring basis are as follows (in thousands):
		As of December 31, 2014
		Fair Value Measurements Using									Total
		Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
		(Level 1)			(Level 2)			(Level 3)
	Contingent consideration to be paid in cash for the acquisitions	$	—		$	—		$	(3,000	)	$	(3,000	)
		As of December 31, 2013
		Fair Value Measurements Using									Total
		Quoted Prices in Active Markets for Identical Assets			Significant Other Observable Inputs			Significant Unobservable Inputs
		(Level 1)			(Level 2)			(Level 3)
	Contingent consideration to be paid in cash for the acquisitions	$	—		$	—		$	(3,667	)	$	(3,667	)
Schedule of Reconciliations of Liabilities Measured and Carried at Fair Value on Recurring Basis, with Significant Unobservable Inputs	Reconciliations of liabilities measured and carried at fair value on a recurring basis with the use of significant unobservable inputs (Level 3) are as follows (in thousands):
		Year Ended December 31,
		2014			2013
	Contingent consideration for acquisitions --
	Balance at beginning of year	$	(3,667	)	$	(6,737	)
	Additions for acquisitions	—			(3,000		)
	Payments on contingent consideration	691			3,425
	Fair value adjustments	—			2,744
	Foreign currency translation adjustment	(24		)	(99		)
	Balance at end of year	$	(3,000	)	$	(3,667	)

Unaudited_Quarterly_Financial_1

Unaudited Quarterly Financial Results (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Financial Information
		2014
		Dec. 31,		Sept. 30,		June 30,		Mar. 31,
		(in thousands, except per share amounts)
	Revenues	$	441,023	$	442,443	$	434,424	$	406,851
	Gross profit	142,537		144,838		141,905		128,155
	Income from continuing operations	19,526		20,723		19,641		13,605
	Income from discontinued operations, net of income taxes	947		1,282		1,148		312
	Net income	$	20,473	$	22,005	$	20,789	$	13,917
	Basic earnings per common share:
	Continuing operations	$	0.38	$	0.39	$	0.36	$	0.25
	Discontinued operations	0.01		0.02		0.02		0.01
	Net income	$	0.39	$	0.41	$	0.38	$	0.26
	Diluted earnings per common share:
	Continuing operations	$	0.37	$	0.38	$	0.36	$	0.25
	Discontinued operations	0.02		0.03		0.02		—
	Net income	$	0.39	$	0.41	$	0.38	$	0.25
		2013
		Dec. 31,		Sept. 30,		June 30,		Mar. 31,
		(in thousands, except per share amounts)
	Revenues	$	396,070	$	394,400	$	380,779	$	351,852
	Gross profit	120,985		119,016		113,105		101,769
	Income from continuing operations	16,321		18,656		6,649		9,514
	Income from discontinued operations, net of income taxes	16,089		1,494		690		15,099
	Net income	$	32,410	$	20,150	$	7,339	$	24,613
	Basic earnings per common share:
	Continuing operations	$	0.3	$	0.35	$	0.12	$	0.18
	Discontinued operations	0.3		0.03		0.02		0.28
	Net income	$	0.6	$	0.38	$	0.14	$	0.46
	Diluted earnings per common share:
	Continuing operations	$	0.3	$	0.34	$	0.12	$	0.18
	Discontinued operations	0.29		0.03		0.02		0.28
	Net income	$	0.59	$	0.37	$	0.14	$	0.46

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The components of accumulated other comprehensive income (loss) were as follows (amounts in thousands):
		Foreign currency translation adjustment			Changes in fair value of derivative, net of tax			Accumulated other comprehensive income (loss)
	Balance at December 31, 2011	$	(1,658	)	$	(380	)	$	(2,038	)
	Other comprehensive income	854			(21		)	833
	Balance at December 31, 2012	(804		)	(401		)	(1,205		)
	Other comprehensive income	1,128			193			1,321
	Balance at December 31, 2013	324			(208		)	116
	Other comprehensive income	(4,772		)	86			(4,686		)
	Balance at December 31, 2014	$	(4,448	)	$	(122	)	$	(4,570	)

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Goodwill	$512,060,000	$514,426,000	$444,084,000
Long-term Debt	415,125,000
Advertising costs	4,800,000	4,000,000	3,300,000
Document Fiscal Year Focus	2014
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$414,800,000

Property_and_Equipment_Details

Property and Equipment (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Document Fiscal Year Focus	2014
Property and equipment	$91,694	$73,964
Less -- accumulated depreciation	47,383	37,916
Total	44,311	36,048
Furniture, fixtures and equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	10,957	7,486
Computer and related equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	21,741	11,358
Computer Software, Intangible Asset [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	41,416	35,943
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	5,637	4,711
Work-in-progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$11,943	$14,466

Property_and_Equipment_Narrati

Property and Equipment (Narratives) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Net book value	$44,311,000	$36,048,000
Depreciation	12,300,000	7,200,000	5,700,000
Document Fiscal Year Focus	2014
Software Development
Property, Plant and Equipment [Line Items]
Net book value	14,000,000	13,400,000
Software Development Work-in-Progress
Property, Plant and Equipment [Line Items]
Net book value	$9,000,000	$10,000,000

Acquisitions_Schedule_of_Purch

Acquisitions (Schedule of Purchase Price Allocation) (Details) (USD $)	1 Months Ended	12 Months Ended	1 Months Ended	0 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	15-May-12	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2014	Dec. 05, 2013
Business Acquisition [Line Items]
contingent consideration maximum							$11,000,000
CyberCoders [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets								915,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets								11,329,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill								37,860,000
Business Acquisition, Effective Date of Acquisition	5-Dec-13
Business Acquisition, Name of Acquired Entity	CyberCoders Holdings, Inc
Business Acquisition, Description of Acquired Entity	a provider of permanent placement services headquartered in Irvine, California.
Business Combination, Reason for Business Combination	The primary reason for the acquisition was to expand the Company's permanent placement services.
Business Combination, Consideration Transferred	96,600,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment								3,327,000
BusinessCombinationRecognizedGoodwill								69,018,000
Goodwill, Acquired During Period		69,018,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets								122,449,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities								9,022,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other								16,839,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities								25,861,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net								96,588,000
Business Acquisition, Cost of Acquired Entity, Cash Paid	93,600,000
Business Acquisition Contingent Consideration At Fair Value Accrued Earn-Out	3,000,000
contingent consideration maximum								11,000,000
Business Combination, Acquisition Related Costs		1,500,000
Whitaker [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition			2-Dec-13
Business Acquisition, Name of Acquired Entity			Whitaker Medical, LLC
Business Acquisition, Description of Acquired Entity			a provider of physician staffing services headquartered in Houston, Texas
Apex Systems
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets				494,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets				172,042,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				251,555,000
Business Acquisition, Effective Date of Acquisition				15-May-12
Business Acquisition, Name of Acquired Entity				Apex Systems, Inc.
Business Acquisition, Description of Acquired Entity				a privately-owned provider of information technology staffing headquartered in Richmond, Virginia.
Business Combination, Reason for Business Combination				The primary reason for the acquisition was to expand the Company's information technology staffing services.
Business Combination, Consideration Transferred				610,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment				902,000
BusinessCombinationRecognizedGoodwill				264,590,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets				689,583,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities				77,905,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other				850,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				78,755,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net				610,828,000
Business Acquisition, Cost of Acquired Entity, Cash Paid				385,000,000	300,000
Business Combination, Acquisition Related Costs						9,800,000
Contractor Relations [Member] | CyberCoders [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill								4,000,000
Contractor Relations [Member] | Apex Systems
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				10,589,000
Customer Relationships [Member] | CyberCoders [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill								860,000
Customer Relationships [Member] | Apex Systems
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				92,147,000
Noncompete Agreements [Member] | CyberCoders [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill								800,000
Noncompete Agreements [Member] | Apex Systems
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				2,076,000
Software [Member] | CyberCoders [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill								18,900,000
Trademarks [Member] | CyberCoders [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill								13,300,000
Trademarks [Member] | Apex Systems
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill				$146,743,000

Acquisitions_Schedule_of_Intan

Acquisitions (Schedule of Intangible Assets Acquired as Part of Business Combination) (Details)	12 Months Ended
	Dec. 31, 2014
Contractor relations | Maximum [Member]
Acquired Intangible Assets [Line Items]
Useful life	5 years
Contractor relations | Minimum [Member]
Acquired Intangible Assets [Line Items]
Useful life	2 years
Customer Relationships [Member] | Maximum [Member]
Acquired Intangible Assets [Line Items]
Useful life	10 years
Customer Relationships [Member] | Minimum [Member]
Acquired Intangible Assets [Line Items]
Useful life	2 years
Non-compete agreements | Maximum [Member]
Acquired Intangible Assets [Line Items]
Useful life	7 years
Non-compete agreements | Minimum [Member]
Acquired Intangible Assets [Line Items]
Useful life	3 years
Computer Software, Intangible Asset [Member]
Acquired Intangible Assets [Line Items]
Useful life	6 years

Acquisitions_Acquisitions_Cost

Acquisitions (Acquisitions Costs, by Acquisition) (Details) (USD $)	1 Months Ended	12 Months Ended	0 Months Ended	3 Months Ended	12 Months Ended	1 Months Ended
Share data in Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2013	15-May-12	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2014	Dec. 05, 2013
Business Acquisition [Line Items]
Maximum earn-out capped							$11,000,000
CyberCoders [Member]
Business Acquisition [Line Items]
BusinessCombinationRecognizedGoodwill								69,018,000
Effective Date of Acquisition	5-Dec-13
Name of Acquired Entity	CyberCoders Holdings, Inc
Business Acquisition, Description of Acquired Entity	a provider of permanent placement services headquartered in Irvine, California.
Reason for Business Combination	The primary reason for the acquisition was to expand the Company's permanent placement services.
Purchase price	96,600,000
Cost of acquired entity, cash paid	93,600,000
Business Acquisition Contingent Consideration At Fair Value Accrued Earn-Out	3,000,000
Business Combination, Acquisition Related Costs		1,500,000
Business Acquisition, Goodwill, Expected Tax Deductible Amount								10,300,000
Maximum earn-out capped								11,000,000
Apex Systems
Business Acquisition [Line Items]
BusinessCombinationRecognizedGoodwill			264,590,000
Effective Date of Acquisition			15-May-12
Name of Acquired Entity			Apex Systems, Inc.
Business Acquisition, Description of Acquired Entity			a privately-owned provider of information technology staffing headquartered in Richmond, Virginia.
Reason for Business Combination			The primary reason for the acquisition was to expand the Company's information technology staffing services.
Purchase price			610,800,000
Cost of acquired entity, cash paid			385,000,000	300,000
Shares of Company's common stock issued (in shares)			14.3
Business Combination, Acquisition Related Costs					$9,800,000
Whitaker [Member]
Business Acquisition [Line Items]
Effective Date of Acquisition						2-Dec-13
Name of Acquired Entity						Whitaker Medical, LLC
Business Acquisition, Description of Acquired Entity						a provider of physician staffing services headquartered in Houston, Texas

Acquisitions_Business_Acquisit

Acquisitions (Business Acquisition, Pro Forma Information) (Details) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition, Pro Forma Information [Abstract]
Revenues	$1,582,699	$1,363,225
Operating income	54,947	49,022
Net income	$88,319	$58,213
Business Acquisition, Pro Forma Income (Loss) from Continuing Operations before Changes in Accounting and Extraordinary Items, Net of Tax, Per Share, Basic	$1.03	$0.94
Basic earnings per share (in dollars per share)	$1.65	$1.12
Business Acquisition, Pro Forma Income (Loss) from Continuing Operations before Changes in Accounting and Extraordinary Items, Net of Tax, Per Share, Diluted	$1.01	$0.92
Diluted earnings per share (in dollars per share)	$1.62	$1.09
Weighted average number of shares outstanding	53,481	52,103
Weighted average number of shares and dilutive shares outstanding	54,555	53,190

Discontinued_Operations_Discon2

Discontinued Operations Discontinued Operations (Details) (USD $)	0 Months Ended			3 Months Ended								12 Months Ended			1 Months Ended
	Feb. 01, 2015	Dec. 02, 2013	Feb. 12, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash Provided by (Used in) Operating Activities, Discontinued Operations												$836,000	($108,000)	$123,000
Cash and cash equivalents				31,714,000				37,350,000				31,714,000	37,350,000	27,479,000	37,350,000	17,739,000
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents				-2,854,000				-2,326,000				-2,854,000	-2,326,000		-2,326,000
Cash				28,860,000				35,024,000				28,860,000	35,024,000		35,024,000
Proceeds from Divestiture of Businesses	123,000,000	28,700,000	33,700,000
Receivable in escrow	6,000,000
Gain on sale of discontinued operations, net of income taxes	25,703,000	16,400,000	14,400,000									0	30,840,000	0
Disposal Group, Including Discontinued Operation, Revenue												137,166,000	153,465,000	207,770,000
Disposal Group Including Discontinued Operations Cost of Services												94,848,000	106,728,000	144,701,000
Disposal Group, Including Discontinued Operation, Gross Profit (Loss)												42,318,000	46,737,000	63,069,000
Disposal Group, Including Discontinued Operation, Operating Income (Loss)												6,519,000	6,938,000	19,766,000
Disposal Group, Including Discontinued Operation, Interest Expense												0	-2,456,000	-4,415,000
Discontinued Operation, Tax Effect of Discontinued Operation		10,400,000	9,100,000									2,830,000	1,950,000	6,161,000
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent				947,000	1,282,000	1,148,000	312,000	16,089,000	1,494,000	690,000	15,099,000	3,689,000	2,532,000	9,190,000
Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation	14,400,000
Accounts receivable, net of allowance of $4,404 and $2,465, respectively				277,146,000				241,905,000				277,146,000	241,905,000		241,905,000
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net				-21,615,000				-20,295,000				-21,615,000	-20,295,000		-20,295,000
Prepaid expenses and income taxes				13,308,000				7,482,000				13,308,000	7,482,000		7,482,000
Disposal Group, Including Discontinued Operation, Prepaid and Other Assets				-1,205,000				-1,204,000				-1,205,000	-1,204,000		-1,204,000
Deferred income tax assets				15,746,000				14,374,000				15,746,000	14,374,000		14,374,000
Disposal Group, Including Discontinued Operation, Deferred Tax Asset, Current				-3,321,000				-3,156,000				-3,321,000	-3,156,000		-3,156,000
Workers' Compensation and Medical Malpractice Receivable, Current				13,370,000				14,390,000				13,370,000	14,390,000		14,390,000
Disposal Group, Including Discontinued Operations, Workers' Compensation and Medical Malpractice Receivable, Current				-5,358,000				-6,810,000				-5,358,000	-6,810,000		-6,810,000
Other current assets				3,121,000				3,071,000				3,121,000	3,071,000		3,071,000
Disposal Group, Including Discontinued Operation, Other Assets, Current				0				-400,000				0	-400,000		-400,000
Disposal Group, Including Discontinued Operation, Assets, Current				34,353,000				34,191,000				34,353,000	34,191,000		34,191,000
Assets, Current				385,904,000				350,437,000				385,904,000	350,437,000		350,437,000
Property and equipment, net				44,311,000				36,048,000				44,311,000	36,048,000		36,048,000
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment				-2,508,000				-2,080,000				-2,508,000	-2,080,000		-2,080,000
Goodwill				512,060,000				514,426,000				512,060,000	514,426,000	444,084,000	514,426,000
Disposal Group, Including Discontinued Operation, Goodwill				-58,637,000				-58,637,000				-58,637,000	-58,637,000		-58,637,000
Identifiable intangible assets, net				250,609,000				273,623,000				250,609,000	273,623,000		273,623,000
Disposal Group, Including Discontinued Operation, Intangible Assets				-11,960,000				-14,232,000				-11,960,000	-14,232,000		-14,232,000
Other non-current assets				7,617,000				8,687,000				7,617,000	8,687,000		8,687,000
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent				-568,000				-639,000				-568,000	-639,000		-639,000
Disposal Group, Including Discontinued Operation, Assets, Noncurrent				73,673,000				75,588,000				73,673,000	75,588,000		75,588,000
Assets				1,274,174,000				1,258,809,000				1,274,174,000	1,258,809,000		1,258,809,000
Disposal Group, Including Discontinued Operation, Assets				0				0				0	0		0
Other Long-term Debt, Current				18,250,000				10,000,000				18,250,000	10,000,000		10,000,000
Accounts payable				7,925,000				7,360,000				7,925,000	7,360,000		7,360,000
Disposal Group, Including Discontinued Operation, Accounts Payable				-951,000				-1,010,000				-951,000	-1,010,000		-1,010,000
Accrued payroll and contract professional pay				82,563,000				72,246,000				82,563,000	72,246,000		72,246,000
Disposal Group, Including Discontinued Operation, Accrued Liabilities				-4,626,000				-4,321,000				-4,626,000	-4,321,000		-4,321,000
Workersb compensation loss reserves				15,564,000				17,123,000				15,564,000	17,123,000		17,123,000
Disposal Group Workers' Compensation and Medical Malpractice Liability, Current				-13,571,000				-15,628,000				-13,571,000	-15,628,000		-15,628,000
Accrued Income Taxes, Current				340,000				13,120,000				340,000	13,120,000		13,120,000
Other current liabilities				20,729,000				26,460,000				20,729,000	26,460,000		26,460,000
Disposal Group, Including Discontinued Operation, Other Liabilities, Current				-1,047,000				-1,027,000				-1,047,000	-1,027,000		-1,027,000
Disposal Group, Including Discontinued Operation, Liabilities, Current				20,195,000				21,986,000				20,195,000	21,986,000		21,986,000
Liabilities, Current				165,566,000				168,295,000				165,566,000	168,295,000		168,295,000
Long-term Debt, Excluding Current Maturities				396,875,000				389,813,000				396,875,000	389,813,000		389,813,000
Deferred income tax liabilities				63,821,000				46,789,000				63,821,000	46,789,000		46,789,000
Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities, Noncurrent				-4,088,000				-3,817,000				-4,088,000	-3,817,000		-3,817,000
Other long-term liabilities				7,937,000				8,597,000				7,937,000	8,597,000		8,597,000
Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent				-1,479,000				-1,365,000				-1,479,000	-1,365,000		-1,365,000
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent				5,567,000				5,182,000				5,567,000	5,182,000		5,182,000
Liabilities				639,766,000				618,676,000				639,766,000	618,676,000		618,676,000
Disposal Group, Including Discontinued Operation, Liabilities				0				0				0	0		0
Cash Provided by (Used in) Investing Activities, Discontinued Operations												-308,000	-183,000	-574,000
Disposal Group, Including Discontinued Operation, General and Administrative Expense												33,078,000	38,991,000	42,334,000
Disposal Group Including Discontinued Operations Amortization of Intangible Assets												2,721,000	808,000	969,000
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax												6,519,000	4,482,000	15,351,000
Life Sciences Europe [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill				4,079,000				4,564,000				4,079,000	4,564,000	3,753,000	4,564,000
Scenario, Previously Reported [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents				31,714,000				37,350,000				31,714,000	37,350,000		37,350,000
Accounts receivable, net of allowance of $4,404 and $2,465, respectively				298,761,000				262,200,000				298,761,000	262,200,000		262,200,000
Prepaid expenses and income taxes				14,513,000				8,686,000				14,513,000	8,686,000		8,686,000
Deferred income tax assets				19,067,000				17,530,000				19,067,000	17,530,000		17,530,000
Workers' Compensation and Medical Malpractice Receivable, Current				18,728,000				21,200,000				18,728,000	21,200,000		21,200,000
Other current assets				3,121,000				3,471,000				3,121,000	3,471,000		3,471,000
Disposal Group, Including Discontinued Operation, Assets, Current				0				0				0	0		0
Assets, Current				385,904,000				350,437,000				385,904,000	350,437,000		350,437,000
Property and equipment, net				46,819,000				38,128,000				46,819,000	38,128,000		38,128,000
Goodwill				570,697,000				573,063,000				570,697,000	573,063,000		573,063,000
Identifiable intangible assets, net				262,569,000				287,855,000				262,569,000	287,855,000		287,855,000
Other non-current assets				8,185,000				9,326,000				8,185,000	9,326,000		9,326,000
Disposal Group, Including Discontinued Operation, Assets, Noncurrent				0				0				0	0		0
Assets				1,274,174,000				1,258,809,000				1,274,174,000	1,258,809,000		1,258,809,000
Other Long-term Debt, Current				18,250,000				10,000,000				18,250,000	10,000,000		10,000,000
Accounts payable				8,876,000				8,370,000				8,876,000	8,370,000		8,370,000
Accrued payroll and contract professional pay				87,189,000				76,567,000				87,189,000	76,567,000		76,567,000
Workersb compensation loss reserves				29,135,000				32,751,000				29,135,000	32,751,000		32,751,000
Accrued Income Taxes, Current				340,000				13,120,000				340,000	13,120,000		13,120,000
Other current liabilities				21,776,000				27,487,000				21,776,000	27,487,000		27,487,000
Disposal Group, Including Discontinued Operation, Liabilities, Current				0				0				0	0		0
Liabilities, Current				165,566,000				168,295,000				165,566,000	168,295,000		168,295,000
Long-term Debt, Excluding Current Maturities				396,875,000				389,813,000				396,875,000	389,813,000		389,813,000
Deferred income tax liabilities				67,909,000				50,606,000				67,909,000	50,606,000		50,606,000
Other long-term liabilities				9,416,000				9,962,000				9,416,000	9,962,000		9,962,000
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent				0				0				0	0		0
Liabilities				$639,766,000				$618,676,000				$639,766,000	$618,676,000		618,676,000
Whitaker [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Business Acquisition, Name of Acquired Entity															Whitaker Medical, LLC
Business Acquisition, Description of Acquired Entity															a provider of physician staffing services headquartered in Houston, Texas

LongTerm_Debt_Details

Long-Term Debt (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 28, 2014	16-May-13
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	$18,250,000
Document Period End Date	31-Dec-14
Senior Secured Debt	415,125,000	399,813,000
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums		15,000,000
Write off of Deferred Debt Issuance Cost	0	14,958,000	813,000
Pledged equity interest in foreign subsidiaries	65.00%
Weighted average interest rate	2.60%
Long-term Debt, Maturities, Repayments of Principal in Year Two	18,250,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	18,250,000
Long-term Debt, Maturities, Repayments of Principal in Year Four	180,063,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	0
Long-term Debt, Maturities, Repayments of Principal after Year Five	180,312,000
Long-term Debt	415,125,000
Maximum [Member]
Debt Instrument [Line Items]
Leverage Ratio in Latest Year of Debt Term	3.25
Leverage ratio	3.5
Revolving Loans and Term A Loans | Eurodollar Rate or Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate borrowings	2.50%
Revolving Loans and Term A Loans | Eurodollar Rate or Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate borrowings	1.75%
Term A Loans, Term B Loans and Revolving Loans [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					500,000,000
Term-B Loan Facility due May 2020 [Member] | Eurodollar [Member]
Debt Instrument [Line Items]
Basis spread on variable rate borrowings	2.50%
Term Loan Facility | $100 million term A loan facility, due May 2017
Debt Instrument [Line Items]
Interest rate at year end	1.90%
Term Loan Facility | Term A Loans, Term B Loans and Revolving Loans [Member]
Debt Instrument [Line Items]
Increase to borrowing capacity available under credit facility					100,000,000
Term Loan Facility | Term-A Loan Facility due May 2018 [Member]
Debt Instrument [Line Items]
Senior Secured Debt	158,813,000	92,500,000
Face amount of term loan					100,000,000
Secured Debt, Increase in Additional Principal Amount				82,500,000
Term Loan Facility | Term-B Loan Facility due May 2020 [Member]
Debt Instrument [Line Items]
Senior Secured Debt	180,312,000	262,813,000
Face amount of term loan					275,000,000
Repayments of Lines of Credit				82,500,000
Debt Instrument, Interest Rate, Stated Percentage					1.00%
Interest rate at year end	3.50%
Revolving Credit Facility
Debt Instrument [Line Items]
Letters of credit outstanding, amount	45,800,000
Revolving Credit Facility | Revolving Credit Facility due May 2018 [Member]
Debt Instrument [Line Items]
Senior Secured Debt	76,000,000	44,500,000
Line of credit facility, maximum borrowing capacity					$125,000,000
Revolving Credit Facility | Revolving Credit Facility due May 2018 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Revolving credit facility, unused portion, commitment fee percentage	0.40%
Revolving Credit Facility | Revolving Credit Facility due May 2018 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Revolving credit facility, unused portion, commitment fee percentage	0.25%
Revolving Credit Facility | Revolving Credit Facility due May 2018 [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest rate at year end	0.17%
Revolving Credit Facility | Revolving Credit Facility due May 2018 [Member] | Spread [Member]
Debt Instrument [Line Items]
Interest rate at year end	2.00%

Goodwill_and_Identifiable_Asse2

Goodwill and Identifiable Assets (Goodwill) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Goodwill, Purchase Accounting Adjustments	$0	$0	$1,805
Goodwill [Roll Forward]
Gross goodwill	514,426	444,084
Accumulated impairment loss	0	0
Goodwill	514,426	444,084
Translation adjustment	-2,366	811
Gross goodwill	512,060	514,426	444,084
Accumulated impairment loss	0	0	0
Goodwill	512,060	514,426	444,084
Goodwill	512,060	514,426	444,084
CyberCoders [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period		69,018
Apex
Goodwill [Roll Forward]
Gross goodwill	289,712	289,712
Accumulated impairment loss	0	0
Goodwill	289,712	289,712
Translation adjustment	-1,761	0
Gross goodwill	287,951	289,712
Accumulated impairment loss	0	0
Goodwill	287,951	289,712
Goodwill	287,951	289,712
Oxford
Goodwill [Roll Forward]
Gross goodwill	220,150	150,619
Accumulated impairment loss	0	0
Goodwill	220,150	150,619
Goodwill, Other Changes		513
Translation adjustment	-120	0
Gross goodwill	220,030	220,150
Accumulated impairment loss	0	0
Goodwill	220,030	220,150
Goodwill	220,030	220,150
Oxford | CyberCoders [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period		69,018
Life Sciences Europe [Member]
Goodwill [Roll Forward]
Gross goodwill	4,564	3,753
Accumulated impairment loss	0	0
Goodwill	4,564	3,753
Translation adjustment	-485	811
Gross goodwill	4,079	4,564
Accumulated impairment loss		0
Goodwill	4,079	4,564
Goodwill	$4,079	$4,564

Goodwill_and_Identifiable_Asse3

Goodwill and Identifiable Assets (Acquired Intangible Assets) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Intangible Assets [Line Items]
Document Period End Date	31-Dec-14
Amortization of intangible assets	$22,130	$20,943	$17,047
Intangible assets subject to amortization:
Gross Carrying Amount	163,027	163,724
Accumulated Amortization	90,743	68,876
Net Carrying Amount	72,284	94,848
Intangible assets not subject to amortization:
Trademarks, Carrying Amount	178,325	178,775
Goodwill	512,060	514,426	444,084
Total
Gross Carrying Amount	341,352	342,499
Net Carrying Amount	250,609	273,623
Customer Relationships [Member]
Intangible assets subject to amortization:
Gross Carrying Amount	101,141	101,697
Accumulated Amortization	53,434	38,930
Net Carrying Amount	47,707	62,767
Customer Relationships [Member] | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	3 months
Customer Relationships [Member] | Maximum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	10 years
Contractor Relations [Member]
Intangible assets subject to amortization:
Gross Carrying Amount	39,332	39,384
Accumulated Amortization	32,021	28,321
Net Carrying Amount	7,311	11,063
Contractor Relations [Member] | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	2 years
Contractor Relations [Member] | Maximum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	7 years
Computer Software, Intangible Asset [Member]
Intangible Assets [Line Items]
Estimated Useful Life	6 years
Intangible assets subject to amortization:
Gross Carrying Amount	18,900	18,900
Accumulated Amortization	3,366	263
Net Carrying Amount	15,534	18,637
Noncompete Agreements [Member]
Intangible assets subject to amortization:
Gross Carrying Amount	3,654	3,743
Accumulated Amortization	1,922	1,362
Net Carrying Amount	$1,732	$2,381
Noncompete Agreements [Member] | Minimum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	2 years
Noncompete Agreements [Member] | Maximum [Member]
Intangible Assets [Line Items]
Estimated Useful Life	7 years

Goodwill_and_Identifiable_Asse4

Goodwill and Identifiable Assets (Future Amortization Expense) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$22,130	$20,943	$17,047
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2013	19,381
2014	16,366
2015	12,078
2016	9,669
2017	7,972
Thereafter	6,818
Net Carrying Amount	$72,284	$94,848

401k_Retirement_Savings_Plan_D

401(k) Retirement Savings Plan, Deferred Compensation Plan and Change in Control Severance Plan (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Employer contributions to 401(k) plans	$7.50	$6	$3.70
Document Fiscal Year Focus	2014

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitment and contingencies [Line Items]
Deferred Rent Credit, Current	$300,000
Long-term Debt
2013	18,250,000
2014	18,250,000
2015	18,250,000
2016	180,063,000
2017	0
Thereafter	180,312,000
Total	415,125,000
Operating Leases
2013	15,012,000
2014	12,809,000
2015	9,871,000
2016	8,015,000
2017	5,796,000
Thereafter	8,516,000
Total	60,019,000
Related Party
2013	1,066,000
2014	1,190,000
2015	1,169,000
2016	1,302,000
2017	1,282,000
Thereafter	6,659,000
Total	12,668,000
Total
2013	16,078,000
2014	13,999,000
2015	11,040,000
2016	9,317,000
2017	7,078,000
Thereafter	15,175,000
Total	72,687,000
Deferred rent liability, noncurrent	4,000,000	3,400,000
Rent expense	17,600,000	15,400,000	11,400,000
Self Insurance Reserve	2,200,000	2,700,000
Workers' Compensation and Medical Malpractice Receivable, Current	13,370,000	14,390,000
Letters of credit outstanding	3,200,000	2,700,000
contingent consideration maximum	11,000,000
Income tax reserve in other long-term liabilities	900,000
Other Liabilities, Current	$20,729,000	$26,460,000
Apex Systems
Total
Number of leased properties owned by related parties (in number of properties)	2

Commitments_and_Contingencies_2

Commitments and Contingencies Legal Proceedings (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Loss Contingencies [Line Items]
Workers' Compensation and Medical Malpractice Receivable, Current	$13,370	$14,390
Other Liabilities, Current	$20,729	$26,460

Commitments_and_Contingencies_3

Commitments and Contingencies Commitments and Contingencies - Income Tax Reserve (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
Liability for Uncertain Tax Positions, Noncurrent	$0.90
Deferred Rent Credit, Current	$0.30

NarrativesDetails

(Narratives)(Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
U.S. federal statutory tax rate	35.00%	35.00%	35.00%
Operating Loss Carryforwards [Line Items]
Valuation allowance	$1,000,000	$1,400,000
Accumulated net earning	154,562,000	146,199,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	800,000	900,000	300,000
Gross deferred tax assets	24,100,000	23,900,000
Gross deferred tax liabilities	71,400,000	54,300,000
Uncertain tax positions	848,000	979,000	376,000	251,000
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	0
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	3,100,000
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	6,300,000
Accumulated net earning	$15,500,000

Income_Taxes_Income_Tax_Compon

Income Taxes (Income Tax Components) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Document Fiscal Year Focus	2014
Current:
Federal	$28,581	$26,284	$15,201
State	5,060	4,910	2,436
Foreign	2,181	1,204	2,726
Total Current	35,822	32,398	20,363
Deferred:
Federal	15,991	4,244	6,358
Foreign	-256	-84	-579
Total Deferred	15,735	4,160	5,779
Total	$51,557	$36,558	$26,142

Income_Taxes_Income_Before_Tax

Income Taxes (Income Before Tax) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Document Fiscal Year Focus	2014
United States	$122,496	$82,970	$56,450
Foreign	2,556	4,728	3,155
Income before income taxes	$125,052	$87,698	$59,605

Income_Taxes_Deferred_Tax_Asse

Income Taxes (Deferred Tax Assets And Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]
Allowance for doubtful accounts	$2,027	$1,716
Employee related accruals	7,240	6,442
State taxes	473	555
Workersb compensation and medical malpractice loss reserves	4,068	4,767
Other	5,259	4,050
Current	19,067	17,530
Intangibles	-59,226	-49,763
Depreciation expense	-13,405	-6,574
Stock-based compensation	3,022	3,761
Net operating loss carryforwards	1,260	1,612
Other	1,554	1,869
Deferred Tax Liabilities, Gross, Noncurrent	-66,795	-49,095
Valuation allowance	-1,114	-1,511
Total deferred income tax assets (liabilities)	($48,842)	($33,076)

Income_Taxes_Tax_Rate_Reconcil

Income Taxes (Tax Rate Reconciliation) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Document Fiscal Year Focus	2014
Income tax provision at the statutory rate	$43,768	$30,694	$20,862
State income taxes, net of federal benefit	4,674	3,807	2,357
Permanent difference b non deductible items	1,608	1,592	1,681
Other	1,507	465	1,242
Total	$51,557	$36,558	$26,142

Income_Taxes_Unrecognized_Tax_

Income Taxes (Unrecognized Tax Benefit) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefit beginning of year	$979	$376	$251
Gross Decreases - tax positions in prior year	0	-177	-34
Reductions for tax positions as a result of a lapse of the applicable statute of limitations	-131	0	0
Gross increases - tax positions in prior year	126	1,240	159
Unrecognized Tax Benefit end of year	848	979	376
Unrecognized Tax Benefits, Reduction Resulting from Discontinued Operations	($126)	($460)	$0

Earnings_per_share_Details

Earnings per share (Details)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Weighted Average Number of Shares Outstanding Reconciliation
Weighted average number of common shares outstanding used to compute basic earnings per share	53,437	53,481	46,739
Dilutive effect of stock-based awards	857	1,074	1,087
Number of shares used to compute diluted earnings per share	54,294	54,555	47,826

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Jul. 21, 2014
Equity [Abstract]
Stock Repurchased and Retired During Period, Value	$100,048,000
Share repurchase program, amount authorized		100,000,000
Stock Repurchased and Retired During Period, Shares	3,400,000
Additional Paid-in Capital [Member]
Equity [Abstract]
Stock Repurchased and Retired During Period, Value	-31,194,000
Retained Earnings [Member]
Equity [Abstract]
Stock Repurchased and Retired During Period, Value	($68,821,000)

Stockbased_Compensation_Incent2

Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date	15.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$24.88
Defined Contribution Plan, Employer Discretionary Contribution Amount	$7,500,000	$6,000,000	$3,700,000
Compensation expense charged to operations related to stock-based compensation	16,199,000	14,411,000	9,706,000
Income tax benefit for stock-based compensation arrangements	4,700,000	5,100,000	3,500,000
Shares available for issuance	3,234,230
Options outstanding (in shares)	694,881	859,945
Document Fiscal Year Focus	2014
2010 Employee Stock Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	3,500,000
Compensation expense charged to operations related to stock-based compensation	1,756,000	1,195,000	755,000
Weighted-average grant-date fair value of options granted	$8.35	$7.16	$3.53
Employee stock purchase plan (in shares)	207,805	203,200	154,934
Award with service conditions [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	705,373	972,364
Share-based awards, grants in period	216,290
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	-436,251
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-47,030
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested and Expected to Vest	609,656
Awards with performance and service conditions [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	381,188	394,874
Share-based awards, grants in period	234,846
Share-based Compensation Arrangement by Share-basd Payment Award, Equity Instruments Other than Options, Market Value Share Count Adjustment for Liability Awards	-12,826
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	-230,837
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-4,869
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested and Expected to Vest	355,782
Liability Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense charged to operations related to stock-based compensation	500,000	1,000,000	1,700,000
Shares vested	-50,000
Deferred Compensation Share-based Arrangements, Liability, Current and Noncurrent	1,453,000	2,500,000	2,000,000	1,852,000
Liability Awards Granted	500,000	1,000,000	1,694,000
Liability Awards Settled During Period	-1,497,000	-500,000	-1,546,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based awards expense, service period	1 year 4 months 24 days
Weighted-average grant-date fair value of options granted			$10.34
Total intrinsic value of options exercised	3,900,000	7,600,000	9,700,000
Unrecognized compensation expense	400,000
Restricted Stock Units and Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	1,086,561	1,367,238
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value		$18.90
Share-based awards, grants in period	451,136
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$18.44
Shares surrendered by the employees to the Company for payment of minimum tax withholding obligations	202,284
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$33.66	$26.17	$16.01
Share-based awards expense, service period	1 year 7 months 6 days
Total intrinsic value of options exercised	21,300,000	15,000,000	13,700,000
Unrecognized compensation expense	14,900,000
Share-based Compensation Arrangement by Share-basd Payment Award, Equity Instruments Other than Options, Market Value Share Count Adjustment for Liability Awards	-12,826
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentOtherThanOptionsMarketValueShareCountAdjustmentWeightedAverageGrantDateFairValue	$33.19
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	-667,088
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-51,899
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Forfeitures	24.42
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested and Expected to Vest	965,438
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Unvested and Expected to Vest, Weighted Average Grant Date Fair Value	$25.21
Director [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	0
Physician Segment [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense charged to operations related to stock-based compensation	600,000	900,000	600,000
Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense charged to operations related to stock-based compensation	$15,600,000	$13,500,000	$9,100,000

Stockbased_Compensation_Incent3

Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan (Assumptions) (Details)	12 Months Ended	3 Months Ended
	Dec. 31, 2014	Mar. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Document Fiscal Year Focus	2014
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield		0.00%
Risk-free interest rate		1.19%
Expected volatility		64.15%
Expected lives		7 years 3 months 18 days

Stockbased_Compensation_Incent4

Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan (Range of Prices) (Details) (USD $)	0 Months Ended		12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price, low end of the range (in dollars per share)			$4.44
Exercise price, high end of the range (in dollars per share)			$16.51
Options outstanding (in shares)	694,881	859,945	694,881
Options outstanding - weighted average remaining contractual life (years)	3 years 6 months	4 years 9 months 18 days	3 years 6 months
Options outstanding - weighted average exercise price (in dollars per share)	$11.33	$10.61	$11.33
Options exercisable - at the end of period (in shares)	624,680		624,680
Options exercisable - weighted average exercise price (in dollars per share)	$11.13		$11.13
$2.82 - 6.68
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price, low end of the range (in dollars per share)			$4.44
Exercise price, high end of the range (in dollars per share)			$8.26
Options outstanding (in shares)	141,321		141,321
Options outstanding - weighted average remaining contractual life (years)			4 years 2 months 12 days
Options outstanding - weighted average exercise price (in dollars per share)	$7.04		$7.04
Options exercisable - at the end of period (in shares)	137,347		137,347
Options exercisable - weighted average exercise price (in dollars per share)	$7.01		$7.01
$6.86 - 10.20
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price, low end of the range (in dollars per share)			$9.19
Exercise price, high end of the range (in dollars per share)			$11.39
Options outstanding (in shares)	231,836		231,836
Options outstanding - weighted average remaining contractual life (years)			3 years 2 months 12 days
Options outstanding - weighted average exercise price (in dollars per share)	$11		$11
Options exercisable - at the end of period (in shares)	198,891		198,891
Options exercisable - weighted average exercise price (in dollars per share)	$11.09		$11.09
$10.46 - 11.39
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price, low end of the range (in dollars per share)			$11.75
Exercise price, high end of the range (in dollars per share)			$12.90
Options outstanding (in shares)	211,724		211,724
Options outstanding - weighted average remaining contractual life (years)			2 years 1 month 6 days
Options outstanding - weighted average exercise price (in dollars per share)	$12.40		$12.40
Options exercisable - at the end of period (in shares)	211,724		211,724
Options exercisable - weighted average exercise price (in dollars per share)	$12.40		$12.40
$11.56 - 12.90
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price, low end of the range (in dollars per share)			$13.31
Exercise price, high end of the range (in dollars per share)			$13.58
Options outstanding (in shares)	35,000		35,000
Options outstanding - weighted average remaining contractual life (years)			2 years
Options outstanding - weighted average exercise price (in dollars per share)	$13.32		$13.32
Options exercisable - at the end of period (in shares)	34,531		34,531
Options exercisable - weighted average exercise price (in dollars per share)	$13.32		$13.32
$12.91 - 16.51
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price, low end of the range (in dollars per share)			$16.51
Exercise price, high end of the range (in dollars per share)			$16.51
Options outstanding (in shares)	75,000		75,000
Options outstanding - weighted average remaining contractual life (years)			7 years 8 months 12 days
Options outstanding - weighted average exercise price (in dollars per share)	$16.51		$16.51
Options exercisable - at the end of period (in shares)	42,187		42,187
Options exercisable - weighted average exercise price (in dollars per share)	$16.51		$16.51
Incentive Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	4,267	69,416	4,267
Options exercisable - at the end of period (in shares)	4,267		4,267

Stockbased_Compensation_Incent5

Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan (Stock Options Activity) (Details) (USD $)	0 Months Ended		3 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2014
Outstanding Stock Options Activity [Roll Forward]
Outstanding at January 1, 2012 (in shares)			859,945	859,945
Exercised (in shares)			-147,163
Canceled (in shares)			-17,901
Outstanding at December 31, 2012 (in shares)	694,881	859,945		694,881
Vested and Expected to Vest at December 31, 2012 (in shares)	691,237			691,237
Exercisable at December 31, 2012 (in shares)	624,680			624,680
Options Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding - weighted average exercise price per share at January 1, 2012			$10.61	$10.61
Exercised, weighted average exercise price per share			$7.51
Canceled, weighted average exercise price per share			$8.25
Outstanding - weighted average exercise price per share at December 31, 2012	$11.33	$10.61		$11.33
Vested and Expected to Vest, weighted average exercise price per share	$11.32			$11.32
Exercisable, weighted average exercise price per share	$11.13			$11.13
Outstanding, weighted average remaining contractual term at January 1, 2012	3 years 6 months	4 years 9 months 18 days		3 years 6 months
Outstanding, weighted average remaining contractual term at December 31, 2012	3 years 6 months	4 years 9 months 18 days		3 years 6 months
Vested and Expected to Vest, weighted average remaining contractual term				3 years 6 months
Exercisable, weighted average remaining contractual term				3 years 2 months 12 days
Options outstanding - aggregate intrinsic value at January 1, 2012			$20,903	$20,903
Options outstanding - aggregate intrinsic value at December 31, 2012	15,189	20,903		15,189
Vested and Expected to Vest, aggregate intrinsic value	15,120			15,120
Exercisable, aggregate intrinsic value	$13,782			$13,782
Incentive Stock Options [Member]
Outstanding Stock Options Activity [Roll Forward]
Outstanding at January 1, 2012 (in shares)			69,416	69,416
Exercised (in shares)			-61,749
Canceled (in shares)			-3,400
Outstanding at December 31, 2012 (in shares)	4,267			4,267
Vested and Expected to Vest at December 31, 2012 (in shares)	4,267			4,267
Exercisable at December 31, 2012 (in shares)	4,267			4,267
Non Qualified Stock Options [Member]
Outstanding Stock Options Activity [Roll Forward]
Outstanding at January 1, 2012 (in shares)			790,529	790,529
Exercised (in shares)			-85,414
Canceled (in shares)			-14,501
Outstanding at December 31, 2012 (in shares)	690,614			690,614
Vested and Expected to Vest at December 31, 2012 (in shares)	686,970			686,970
Exercisable at December 31, 2012 (in shares)	620,413			620,413

Stockbased_Compensation_Incent6

Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan Stock-based Compensation: Incentive Award Plan and Employee Stock Purchase Plan (RSU and RSAs) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	3,234,230
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Unvested RSUs and RSAs outstanding at December 31, 2012, weighted average grant date fair value (in dollars per share)	$24.88
Restricted Stock Units and Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested RSUs and RSAs outstanding at January 1, 2012 (in shares)	1,367,238
Granted (in shares)	451,136
Market value share count adjustment for liability awards (in shares)	12,826
Vested (in shares)	667,088
Forfeited (in shares)	51,899
Unvested RSUs and RSAs outstanding at December 31, 2012 (in shares)	1,086,561	1,367,238
Unvested and expected to vest RSUs and RSAs outstanding at December 31, 2012 (in shares)	965,438
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Unvested RSUs and RSAs outstanding at January 1, 2012, weighted average grant date fair value (in dollars per share)	$18.90
Granted, weighted average grant date fair value (in dollars per share)	$33.66	$26.17	$16.01
Vested, weighted average grant date fair value (in dollars per share)	$18.44
Unvested RSUs and RSAs outstanding at December 31, 2012, weighted average grant date fair value (in dollars per share)		$18.90
Unvested and expected to vest RSUs and RSAs outstanding at December 31, 2012, weighted average grant date fair value (in dollars per share)	$25.21

Business_Segments_Segment_Repo

Business Segments (Segment Reporting Information) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
									segment
Segment Reporting Information
Revenues	$441,023,000	$442,443,000	$434,424,000	$406,851,000	$396,070,000	$394,400,000	$380,779,000	$351,852,000	$1,724,741,000	$1,523,101,000	$1,031,935,000
Gross profit	142,537,000	144,838,000	141,905,000	128,155,000	120,985,000	119,016,000	113,105,000	101,769,000	557,435,000	454,875,000	321,254,000
Operating Income									137,782,000	116,587,000	73,013,000
Depreciation									12,300,000	7,200,000	5,700,000
Amortization of intangible assets									22,130,000	20,943,000	17,047,000
Assets	1,274,174,000				1,258,809,000				1,274,174,000	1,258,809,000
Reportable segments (in number of segments)									3
Apex
Segment Reporting Information
Revenues									1,190,052,000	1,059,993,000	617,844,000
Gross profit									335,322,000	294,611,000	174,968,000
Operating Income									121,334,000	98,588,000	57,191,000
Amortization of intangible assets									16,356,000	19,524,000	15,665,000
Oxford
Segment Reporting Information
Revenues									493,320,000	423,670,000	375,196,000
Gross profit									208,607,000	147,348,000	132,034,000
Operating Income									66,315,000	60,544,000	57,703,000
Amortization of intangible assets									5,491,000	965,000	437,000
Life Sciences Europe [Member]
Segment Reporting Information
Revenues									41,369,000	39,438,000	38,895,000
Gross profit									13,506,000	12,916,000	14,252,000
Operating Income									3,878,000	5,574,000	4,481,000
Amortization of intangible assets									274,000	364,000	654,000
Corporate
Segment Reporting Information
Operating Income									-53,745,000	-48,119,000	-46,362,000
Amortization of intangible assets									$9,000	$90,000	$291,000

Business_Segments_Revenue_by_G

Business Segments (Revenue by Geographical Areas) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Total Revenues	$441,023	$442,443	$434,424	$406,851	$396,070	$394,400	$380,779	$351,852	$1,724,741	$1,523,101	$1,031,935
Domestic [Member]
Revenues:
Total Revenues									1,643,598	1,446,805	958,342
Foreign [Member]
Revenues:
Total Revenues									$81,143	$76,296	$73,593

Business_Segments_LongLived_As

Business Segments (Long-Lived Assets) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$441,023	$442,443	$434,424	$406,851	$396,070	$394,400	$380,779	$351,852	$1,724,741	$1,523,101	$1,031,935
Long-Lived Assets	51,928				44,735				51,928	44,735	40,105
Domestic [Member]
Segment Reporting Information [Line Items]
Revenues									1,643,598	1,446,805	958,342
Long-Lived Assets	49,837				42,341				49,837	42,341	38,099
Foreign [Member]
Segment Reporting Information [Line Items]
Revenues									81,143	76,296	73,593
Long-Lived Assets	$2,091				$2,394				$2,091	$2,394	$2,006

Fair_Value_Measurements_Fair_V1

Fair Value Measurements (Fair Value Inputs, Liabilities, Quantitative Information) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value Inputs, Liabilities, Quantitative Information
Long-term debt	$415,125,000
Contingent Consideration Liability [Member]
Fair Value Inputs, Liabilities, Quantitative Information
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	3,000,000	3,667,000	6,737,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Acquisitions	0	3,000,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Payments	691,000	3,425,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	0	-2,744,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	24,000	99,000
Significant other observable inputs (Level 2)
Fair Value Inputs, Liabilities, Quantitative Information
Long-term debt, fair value	414,800,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Inputs, Liabilities, Quantitative Information
Obligations, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Significant other observable inputs (Level 2)
Fair Value Inputs, Liabilities, Quantitative Information
Obligations, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Liabilities, Quantitative Information
Obligations, Fair Value Disclosure	-3,000,000	-3,667,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Fair Value Inputs, Liabilities, Quantitative Information
Obligations, Fair Value Disclosure	$3,000,000	$3,667,000

Fair_Value_Measurements_Recurr

Fair Value Measurements (Recurring Basis) (Details) (Fair Value, Measurements, Recurring [Member], USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration to be paid in cash for the acquisitions	$0	$0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration to be paid in cash for the acquisitions	3,000	3,667
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration to be paid in cash for the acquisitions	-3,000	-3,667
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration to be paid in cash for the acquisitions	$0	$0

Fair_Value_Measurements_Liabil

Fair Value Measurements (Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation) (Details) (Contingent Consideration Liability [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Contingent Consideration Liability [Member]
Contingent consideration for acquisitions
Balance at beginning of period	($3,667)	($6,737)
Additions for acquisitions	0	-3,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Payments	691	3,425
Fair value adjustment	0	2,744
Foreign currency translation adjustment	-24	-99
Balance at end of period	($3,000)	($3,667)

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	0 Months Ended
	Feb. 01, 2015	Dec. 02, 2013	Feb. 12, 2013	Jul. 21, 2014	Jan. 16, 2015
Subsequent Event [Line Items]
Share repurchase program, amount authorized				$100,000,000
Proceeds from Divestiture of Businesses	123,000,000	28,700,000	33,700,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Share repurchase program, amount authorized					100,000,000
Proceeds from Divestiture of Businesses	$123,000,000

Unaudited_Quarterly_Financial_2

Unaudited Quarterly Financial Results (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Revenues	$441,023	$442,443	$434,424	$406,851	$396,070	$394,400	$380,779	$351,852	$1,724,741	$1,523,101	$1,031,935
Gross profit	142,537	144,838	141,905	128,155	120,985	119,016	113,105	101,769	557,435	454,875	321,254
Income from continuing operations	19,526	20,723	19,641	13,605	16,321	18,656	6,649	9,514	73,495	51,140	33,463
Income from discontinued operations, net of income taxes	947	1,282	1,148	312	16,089	1,494	690	15,099	3,689	2,532	9,190
Net income	20,473	22,005	20,789	13,917	32,410	20,150	7,339	24,613	77,184	84,512	42,653
Earnings Per Share, Basic [Abstract]
Continuing operations	$0.38	$0.39	$0.36	$0.25	$0.30	$0.35	$0.12	$0.18	$1.38	$0.96	$0.72
Discontinued operations	$0.01	$0.02	$0.02	$0.01	$0.30	$0.03	$0.02	$0.28	$0.06	$0.62	$0.19
Net income	$0.39	$0.41	$0.38	$0.26	$0.60	$0.38	$0.14	$0.46	$1.44	$1.58	$0.91
Earnings Per Share, Diluted [Abstract]
Continuing operations	$0.37	$0.38	$0.36	$0.25	$0.30	$0.34	$0.12	$0.18	$1.35	$0.94	$0.70
Discontinued operations	$0.02	$0.03	$0.02	$0	$0.29	$0.03	$0.02	$0.28	$0.07	$0.61	$0.19
Net income	$0.39	$0.41	$0.38	$0.25	$0.59	$0.37	$0.14	$0.46	$1.42	$1.55	$0.89
Apex Segment [Member]
Quarterly Financial Information Disclosure [Abstract]
Revenues									1,190,052	1,059,993	617,844
Gross profit									$335,322	$294,611	$174,968

Schedule_II_Valuation_and_Qual1

Schedule II - Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts and Bilinig Adjustments
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$2,465	$3,395	$2,468
Provisions	6,680	1,474	-446
Deductions	-4,741	-2,404	1,373
Balance at end of year	4,404	2,465	3,395
Allowance for Workers' Compensation and Medical Malpractice Loss Reserves
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	17,123	17,037	16,391
Provisions	2,211	5,850	3,399
Deductions	-3,770	-5,764	-2,753
Balance at end of year	$15,564	$17,123	$17,037

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment	($4,448)	$324	($804)	($1,658)
Accumulated Other Comprehensive Income (Loss), Derivatives, Net of Tax	-122	-208	-401	-380
Changes in fair value of derivative, net of tax	86	193	-21
Other Comprehensive Income (Loss), Net of Tax	-4,686	1,321	833
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	-4,772	1,128	854
Accumulated other comprehensive income (loss)	($4,570)	$116	($1,205)	($2,038)