CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 93,663	$ 63,130
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of intangible assets	87	79
Depreciation expense	24,280	25,703
Stock-based compensation expense-restricted stock and stock units	20,205	25,447
Excess tax benefits from stock-based compensation	(2,895)	(944)
Provision for deferred income taxes	(13,973)	(6,781)
Provision for doubtful accounts receivable	4,644	2,309
Changes in assets and liabilities:
Increase in accounts receivable	(44,317)	(65,517)
(Decrease) increase in accounts payable, accrued expenses, accrued payroll costs and retirement obligations	(3,114)	17,479
Increase in income taxes payable	38,650	28,770
Change in other assets, net of change in other liabilities	(1,944)	(1,793)
Net cash flows provided by operating activities	115,286	87,882
CASH FLOWS FROM INVESTING ACTIVITIES:
Payment for acquisitions, net of cash acquired	(1,484)
Capital expenditures	(24,211)	(28,375)
Increase in trusts for employee benefits and retirement plans	(3,596)	(2,785)
Net cash flows used in investing activities	(29,291)	(31,160)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchases of common stock	(101,380)	(91,545)
Cash dividends paid	(41,874)	(40,307)
Increase in notes payable and other indebtedness	(55)	(60)
Excess tax benefits from stock-based compensation	2,895	944
Proceeds from exercises of stock options	35,391	13,693
Net cash flows used in financing activities	(105,023)	(117,275)
Effect of exchange rate changes on cash and cash equivalents	(1,730)	6,487
Net decrease in cash and cash equivalents	(20,758)	(54,066)
Cash and cash equivalents at beginning of period	279,336	315,137
Cash and cash equivalents at end of period	258,578	261,071
Cash paid during the period for:
Interest	208	273
Income taxes, net of refunds	$ 35,507	$ 19,251