Reportable Segments - Operations of Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Net service revenues	$ 322,201	$ 312,611
Gross profit	97,189	94,740
Operating expenses	88,450	85,202
Income before income taxes	8,739	9,538
Flexible Billings
Segment Reporting Information [Line Items]
Net service revenues	309,636	300,532
Direct Hire Fees
Segment Reporting Information [Line Items]
Net service revenues	12,565	12,079
Operating Segments \| Tech
Segment Reporting Information [Line Items]
Net service revenues	216,588	213,639
Gross profit	61,791	60,217
Operating Segments \| Tech \| Flexible Billings
Segment Reporting Information [Line Items]
Net service revenues	211,209	208,438
Operating Segments \| Tech \| Direct Hire Fees
Segment Reporting Information [Line Items]
Net service revenues	5,379	5,201
Operating Segments \| FA
Segment Reporting Information [Line Items]
Net service revenues	82,492	73,072
Gross profit	28,821	25,689
Operating Segments \| FA \| Flexible Billings
Segment Reporting Information [Line Items]
Net service revenues	75,306	66,194
Operating Segments \| FA \| Direct Hire Fees
Segment Reporting Information [Line Items]
Net service revenues	7,186	6,878
Operating Segments \| GS
Segment Reporting Information [Line Items]
Net service revenues	23,121	25,900
Gross profit	6,577	8,834
Operating Segments \| GS \| Flexible Billings
Segment Reporting Information [Line Items]
Net service revenues	23,121	25,900
Operating Segments \| GS \| Direct Hire Fees
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.

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 210.5-03.1,2)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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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

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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.

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+ 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

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