Reconciliation of Revenue and Operating Income (Loss) by Reportable Segment to Consolidated Results (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Net service revenues	$ 1,084,342	$ 1,023,684
Operating income	102,109	89,505
Amortization of intangible assets	333	433
Interest income, net	(238)	(304)
Income before income taxes	102,014	89,376
Temporary and consultant staffing
Segment Reporting Information [Line Items]
Net service revenues	857,570	823,422
Operating income	77,485	73,180
Permanent placement staffing
Segment Reporting Information [Line Items]
Net service revenues	92,625	83,377
Operating income	17,275	12,585
Risk consulting and internal audit services
Segment Reporting Information [Line Items]
Net service revenues	134,147	116,885
Operating income	$ 7,349	$ 3,740