Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Operating Activities:
Net earnings	$ 92,729	$ 88,727	$ 266,002	$ 249,470
Adjustments to reconcile net earnings to net cash from operating activities:
Provision for losses (recoveries) on accounts receivable	1,496	463	2,537	(392)
Deferred income tax (benefit) expense	(33,185)	4,588	(20,245)	4,330
Excess tax benefits from stock plans	0	(59)	(1,683)	(4,291)
Stock compensation expense	11,015	11,320	33,060	32,846
Depreciation and amortization	12,629	10,030	35,581	29,245
Other	187	1,260	636	1,683
Changes in operating assets and liabilities:
Increase in accounts receivable	(5,115)	(23,520)	(14,482)	(73,812)
Increase in other current assets	(4,702)	(7,195)	(5,278)	(3,629)
(Decrease) increase in accounts payable and accrued expenses	(8,875)	(23,267)	34,815	60,966
Increase in income taxes payable, net	30,114	6,819	14,640	12,961
Net cash from operating activities	96,293	69,166	345,583	309,377
Investing Activities:
(Increase) decrease in short-term investments, net	(9,925)	113	(99,690)	211
Purchase of property and equipment	(15,482)	(10,170)	(42,691)	(37,072)
Other, net	306	(104)	1,126	275
Net cash from investing activities	(25,101)	(10,161)	(141,255)	(36,586)
Financing Activities:
Proceeds from issuance of common stock	33,615	24,599	52,092	45,001
Repurchases of common stock	(85,925)	(87,227)	(125,206)	(193,493)
Excess tax benefits from stock plans	0	59	1,683	4,291
Dividends paid	0	0	(61,899)	(59,358)
Purchase of noncontrolling interest	0	0	(7,730)	0
Distributions to noncontrolling interest	(1,161)	(1,177)	(1,161)	(1,177)
Net cash from financing activities	(53,471)	(63,746)	(142,221)	(204,736)
Effect of exchange rate changes on cash and cash equivalents	6,500	8,136	(12,619)	5,231
Increase in cash and cash equivalents	24,221	3,395	49,488	73,286
Cash and cash equivalents at beginning of period	1,286,109	1,364,247	1,260,842	1,294,356
Cash and cash equivalents at end of period	1,310,330	1,367,642	1,310,330	1,367,642
Taxes Paid:
Income taxes	$ 147,248	$ 50,911	$ 174,199	$ 155,006