Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Operating Activities:
Net earnings	$ 88,727	$ 106,876	$ 249,470	$ 293,103
Adjustments to reconcile net earnings to net cash from operating activities:
Provision for losses on accounts receivable	463	(629)	(392)	1,161
Deferred income tax expense (benefit)	4,588	(9,328)	4,330	(9,663)
Excess tax benefits from stock plans	(59)	(537)	(4,291)	(5,068)
Stock compensation expense	11,320	12,738	32,846	33,446
Depreciation and amortization	10,030	9,199	29,245	27,630
Gain on sale of assets	(13)	(3)	(143)	(54)
Other	1,273	1,210	1,826	1,828
Changes in operating assets and liabilities:
Increase in accounts receivable	(23,520)	(4,312)	(73,812)	(11,802)
Increase in other current assets	(7,195)	(8,344)	(3,629)	(5,863)
(Decrease) increase in accounts payable and accrued expenses	(23,267)	(24,070)	60,966	14,060
Increase in income taxes payable, net	6,819	10,505	12,961	10,417
Net cash from operating activities	69,166	93,305	309,377	349,195
Investing Activities:
Purchase of property and equipment	(10,170)	(20,619)	(37,072)	(58,854)
Proceeds from sale of property and equipment	41	24	294	109
Other, net	(32)	(632)	192	(2,676)
Net cash from investing activities	(10,161)	(21,227)	(36,586)	(61,421)
Financing Activities:
Proceeds from issuance of common stock	24,599	30,966	45,001	54,591
Repurchases of common stock	(87,227)	(43,298)	(193,493)	(108,572)
Excess tax benefits from stock plans	59	537	4,291	5,068
Dividends paid	0	0	(59,358)	(53,014)
Distributions to noncontrolling interest	(1,177)	(822)	(1,177)	(822)
Net cash from financing activities	(63,746)	(12,617)	(204,736)	(102,749)
Effect of exchange rate changes on cash and cash equivalents	8,136	(24,477)	5,231	(8,676)
Increase in cash and cash equivalents	3,395	34,984	73,286	176,349
Cash and cash equivalents at beginning of period	1,364,247	1,225,830	1,294,356	1,084,465
Cash and cash equivalents at end of period	1,367,642	1,260,814	1,367,642	1,260,814
Interest and Taxes Paid:
Interest	27	48	447	65
Income taxes	$ 50,911	$ 65,856	$ 155,006	$ 183,167