Condensed Consolidated Statements of Cash Flows (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Operating Activities:
Net earnings	$ 95,020	$ 90,409	$ 186,227	$ 151,719
Adjustments to reconcile net earnings to net cash provided by operating activities:
Provision for losses on accounts receivable	(63)	(618)	1,790	1,825
Deferred income tax expense (benefit)	1,601	10,814	(335)	3,086
Excess tax benefits from stock plans	(2,285)	(4,107)	(4,531)	(8,119)
Stock compensation expense	10,236	11,003	20,708	22,201
Depreciation and amortization	9,257	9,110	18,431	18,505
Gain on sale of assets	(21)	(109)	(51)	(404)
Other	311	367	618	845
Changes in operating assets and liabilities:
Increase in accounts receivable	(14,173)	(219,602)	(7,490)	(232,567)
Decrease in other current assets	3,896	2,947	2,481	1,136
Increase in accounts payable and accrued expenses	7,943	121,941	38,130	165,110
(Decrease) increase in income taxes payable, net	(33,665)	(1,609)	(88)	24,332
Net cash provided by operating activities	78,057	20,546	255,890	147,669
Investing Activities:
(Increase) decrease in short-term investments, net	(449)	6	(538)	(30)
Purchase of property and equipment	(17,110)	(8,118)	(38,235)	(15,700)
Proceeds from sale of property and equipment	42	111	85	170
Other	(64)	(707)	(1,506)	(895)
Net cash used in investing activities	(17,581)	(8,708)	(40,194)	(16,455)
Financing Activities:
Proceeds from issuance of common stock	15,821	11,020	23,625	23,240
Repurchases of common stock	(45,690)	(53,649)	(65,274)	(71,668)
Excess tax benefits from stock plans	2,285	4,107	4,531	8,119
Dividends paid	(53,014)	(42,397)	(53,014)	(42,397)
Net cash used in financing activities	(80,598)	(80,919)	(90,132)	(82,706)
Effect of exchange rate changes on cash and cash equivalents	7,481	(12,267)	15,801	(14,137)
(Decrease) increase in cash and cash equivalents	(12,641)	(81,348)	141,365	34,371
Cash and cash equivalents at beginning of period	1,238,471	1,041,648	1,084,465	925,929
Cash and cash equivalents at end of period	1,225,830	960,300	1,225,830	960,300
Interest and Taxes Paid:
Interest	13	35	17	44
Income taxes	$ 91,035	$ 56,846	$ 117,311	$ 76,842