Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Operating Activities:
Net earnings	$ 84,021	$ 95,020	$ 160,743	$ 186,227
Adjustments to reconcile net earnings to net cash from operating activities:
Provision for losses on accounts receivable	(388)	(63)	(855)	1,790
Deferred income tax (benefit) expense	(5,739)	1,601	(258)	(335)
Excess tax benefits from stock plans	(806)	(2,285)	(4,232)	(4,531)
Stock compensation expense	10,926	10,236	21,526	20,708
Depreciation and amortization	9,670	9,257	19,215	18,431
Gain on sale of assets	(65)	(21)	(130)	(51)
Other	271	311	553	618
Changes in operating assets and liabilities:
Increase in accounts receivable	(63,260)	(14,173)	(50,292)	(7,490)
Decrease in other current assets	1,642	3,896	3,566	2,481
Increase in accounts payable and accrued expenses	70,674	7,943	84,233	38,130
(Decrease) increase in income taxes payable, net	(14,132)	(33,665)	6,142	(88)
Net cash from operating activities	92,814	78,057	240,211	255,890
Investing Activities:
Decrease (increase) in short-term investments, net	15,878	(449)	98	(538)
Purchase of property and equipment	(9,814)	(17,110)	(26,902)	(38,235)
Proceeds from sale of property and equipment	141	42	253	85
Other	(232)	(64)	126	(1,506)
Net cash from investing activities	5,973	(17,581)	(26,425)	(40,194)
Financing Activities:
Proceeds from issuance of common stock	7,482	15,821	20,402	23,625
Repurchases of common stock	(84,401)	(45,690)	(106,266)	(65,274)
Excess tax benefits from stock plans	806	2,285	4,232	4,531
Dividends paid	(59,358)	(53,014)	(59,358)	(53,014)
Net cash from financing activities	(135,471)	(80,598)	(140,990)	(90,132)
Effect of exchange rate changes on cash and cash equivalents	(11,984)	7,481	(2,905)	15,801
(Decrease) increase in cash and cash equivalents	(48,668)	(12,641)	69,891	141,365
Cash and cash equivalents at beginning of period	1,412,915	1,238,471	1,294,356	1,084,465
Cash and cash equivalents at end of period	1,364,247	1,225,830	1,364,247	1,225,830
Interest and Taxes Paid:
Interest	233	13	420	17
Income taxes	$ 77,583	$ 91,035	$ 104,095	$ 117,311