Business Segments (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net service revenues	$ 937,966	$ 769,090	$ 1,818,835	$ 1,506,263
Operating income (loss)	61,086	22,339	105,489	34,799
Amortization of intangible assets	40	46	79	315
Interest income, net	(238)	(94)	(450)	(168)
Income before income taxes	61,284	22,387	105,860	34,652
Temporary and Consultant Staffing [Member]
Net service revenues	752,369	619,797	1,467,051	1,218,483
Operating income (loss)	46,241	23,571	84,311	40,517
Permanent Placement Staffing [Member]
Net service revenues	80,663	56,133	148,267	104,772
Operating income (loss)	13,875	5,540	21,742	8,656
Risk Consulting and Internal Audit Services [Member]
Net service revenues	104,934	93,160	203,517	183,008
Operating income (loss)	$ 970	$ (6,772)	$ (564)	$ (14,374)