CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net service revenues	$ 4,111,213	$ 3,776,976	$ 3,175,093
Direct costs of services, consisting of payroll, payroll taxes, insurance costs and reimbursable expenses	2,462,153	2,287,374	1,981,060
Gross margin	1,649,060	1,489,602	1,194,033
Selling, general and administrative expenses	1,305,614	1,240,184	1,079,033
Amortization of intangible assets	398	153	411
Interest income, net	(1,197)	(951)	(579)
Income before income taxes	344,245	250,216	115,168
Provision for income taxes	134,303	100,294	49,099
Net income	209,942	149,922	66,069
Net income available to common stockholders - diluted	$ 208,867	$ 147,772	$ 63,729
Net income per share (Note L):
Basic	$ 1.51	$ 1.05	$ 0.45
Diluted	$ 1.50	$ 1.04	$ 0.44
Shares:
Basic	138,201	140,479	142,833
Diluted	139,409	141,790	144,028
Cash dividends declared per share	$ 0.60	$ 0.56	$ 0.52