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, 2013	Mar. 31, 2012
Segment Reporting Information [Line Items]
Net service revenues	$ 1,023,684	$ 1,015,444
Operating income (loss)	89,505	80,065
Amortization of intangible assets	433	35
Interest income, net	(304)	(234)
Income before income taxes	89,376	80,264
Temporary and consultant staffing
Segment Reporting Information [Line Items]
Net service revenues	823,422	829,657
Operating income (loss)	73,180	69,154
Permanent placement staffing
Segment Reporting Information [Line Items]
Net service revenues	83,377	82,862
Operating income (loss)	12,585	13,266
Risk consulting and internal audit services
Segment Reporting Information [Line Items]
Net service revenues	116,885	102,925
Operating income (loss)	$ 3,740	$ (2,355)