Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Operating Activities:
Net earnings	$ 118,329	$ 91,728	$ 225,661	$ 175,923
Adjustments to reconcile net earnings to net cash from operating activities:
Provision for losses (recoveries) on accounts receivable	584	496	861	(619)
Deferred income tax expense	8,986	2,891	20,923	10,085
Excess tax benefits from stock plans	(366)	(495)	(1,846)	(984)
Stock compensation expense	11,663	11,877	21,570	22,171
Depreciation and amortization	11,420	12,417	22,949	24,799
Other	27	68	113	206
Changes in operating assets and liabilities:
Decrease (increase) in accounts receivable	63,234	(84,618)	16,444	(72,390)
Increase in accounts payable and accrued expenses	8,038	61,377	22,933	90,923
Decrease in income taxes payable, net	(39,000)	(47,370)	(15,868)	(29,165)
(Increase) decrease in other current assets	(1,187)	(3,485)	2,382	(2,206)
Net cash from operating activities	181,728	44,886	316,122	218,743
Investing Activities:
Purchase of short-term investments	(46,986)	(15,301)	(47,008)	(96,431)
Proceeds from maturities of short-term investments	0	15,643	40,296	36,619
Purchase of property and equipment	(12,912)	(9,635)	(22,357)	(18,395)
Escrow deposit for land acquisition	0	(27,101)	0	(27,101)
Other, net	(14)	(1,536)	184	134
Net cash from investing activities	(59,912)	(37,930)	(28,885)	(105,174)
Financing Activities:
Proceeds from issuance of common stock	25,047	22,125	60,095	30,017
Repurchases of common stock	(128,137)	(131,391)	(205,505)	(358,116)
Excess tax benefits from stock plans	366	495	1,846	984
Dividends paid	(68,781)	(62,807)	(68,781)	(62,807)
Distributions to noncontrolling interest	0	0	(857)	(85)
Net cash from financing activities	(171,505)	(171,578)	(213,202)	(390,007)
Effect of exchange rate changes on cash and cash equivalents	2,272	4,137	(15,415)	(653)
(Decrease) increase in cash and cash equivalents	(47,417)	(160,485)	58,620	(277,091)
Cash and cash equivalents at beginning of period	1,033,144	1,131,046	927,107	1,247,652
Cash and cash equivalents at end of period	985,727	970,561	985,727	970,561
Taxes Paid:
Income taxes	$ 101,389	$ 105,963	$ 129,650	$ 133,459