CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 151,323	$ 107,298
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of intangible assets	187	118
Depreciation expense	36,323	38,509
Stock-based compensation expense-restricted stock and stock units	30,891	38,193
Excess tax benefits from stock-based compensation	(3,104)	(1,087)
Provision for deferred income taxes	(19,544)	(7,186)
Provision for doubtful accounts receivable	7,657	3,940
Changes in assets and liabilities:
Increase in accounts receivable	(68,578)	(99,490)
Increase in accounts payable, accrued expenses, accrued payroll costs and retirement obligations	19,201	56,280
Increase in income taxes payable	37,019	30,701
Change in other assets, net of change in other liabilities	(121)	(7,608)
Net cash flows provided by operating activities	191,254	159,668
CASH FLOWS FROM INVESTING ACTIVITIES:
Payment for acquisitions, net of cash acquired	(1,525)
Capital expenditures	(35,816)	(41,708)
Increase in trusts for employee benefits and retirement plans	(5,752)	(4,812)
Net cash flows used in investing activities	(43,093)	(46,520)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchases of common stock	(117,468)	(140,391)
Cash dividends paid	(62,691)	(60,024)
Increase in notes payable and other indebtedness	(76)	(92)
Excess tax benefits from stock-based compensation	3,104	1,087
Proceeds from exercises of stock options	37,843	15,279
Net cash flows used in financing activities	(139,288)	(184,141)
Effect of exchange rate changes on cash and cash equivalents	1,219	(1,418)
Net increase (decrease) in cash and cash equivalents	10,092	(72,411)
Cash and cash equivalents at beginning of period	279,336	315,137
Cash and cash equivalents at end of period	289,428	242,726
Cash paid during the period for:
Interest	308	409
Income taxes, net of refunds	80,158	44,857
Non-cash items:
Stock repurchases awaiting settlement	$ 11,639