Reportable Segments - Operations of Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Net service revenues	$ 312,611us-gaap_SalesRevenueServicesNet	$ 282,024us-gaap_SalesRevenueServicesNet
Gross profit	94,740us-gaap_GrossProfit	83,526us-gaap_GrossProfit
Operating expenses	85,202us-gaap_OperatingExpenses	76,430us-gaap_OperatingExpenses
Income from continuing operations, before income taxes	9,538	7,096
Flexible Billings [Member]
Segment Reporting Information [Line Items]
Net service revenues	300,532	272,334
Direct Hire Fees [Member]
Segment Reporting Information [Line Items]
Net service revenues	12,079	9,690
Technology [Member]
Segment Reporting Information [Line Items]
Net service revenues	213,639	196,471
Gross profit	60,217	55,055
Technology [Member] \| Flexible Billings [Member]
Segment Reporting Information [Line Items]
Net service revenues	208,438	192,463
Technology [Member] \| Direct Hire Fees [Member]
Segment Reporting Information [Line Items]
Net service revenues	5,201	4,008
Finance and Accounting [Member]
Segment Reporting Information [Line Items]
Net service revenues	73,072	62,782
Gross profit	25,689	21,876
Finance and Accounting [Member] \| Flexible Billings [Member]
Segment Reporting Information [Line Items]
Net service revenues	66,194	57,100
Finance and Accounting [Member] \| Direct Hire Fees [Member]
Segment Reporting Information [Line Items]
Net service revenues	6,878	5,682
Government Solutions [Member]
Segment Reporting Information [Line Items]
Net service revenues	25,900	22,771
Gross profit	8,834	6,595
Government Solutions [Member] \| Flexible Billings [Member]
Segment Reporting Information [Line Items]
Net service revenues	25,900	22,771
Government Solutions [Member] \| Direct Hire Fees [Member]
Segment Reporting Information [Line Items]
Net service revenues	$ 0	$ 0

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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- Definition

Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h)(1)(i))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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- Definition

Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

+ References

No definition available.

+ Details

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- Definition

Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(d))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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- Details

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- Details

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- Details

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- Details

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- Details

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