Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Activities:
Net earnings	$ 379,460us-gaap_ProfitLoss	$ 350,011us-gaap_ProfitLoss	$ 332,969us-gaap_ProfitLoss
Adjustments to reconcile net earnings to net cash from operating activities:
Provision for losses (recoveries) on accounts receivable	763us-gaap_ProvisionForDoubtfulAccounts	2,116us-gaap_ProvisionForDoubtfulAccounts	(90)us-gaap_ProvisionForDoubtfulAccounts
Deferred income tax (benefit) expense	(6,576)us-gaap_DeferredIncomeTaxExpenseBenefit	(20,975)us-gaap_DeferredIncomeTaxExpenseBenefit	11,639us-gaap_DeferredIncomeTaxExpenseBenefit
Excess tax benefits from stock plans	(1,115)	(2,339)	(5,401)
Stock compensation expense	42,533us-gaap_ShareBasedCompensation	43,813us-gaap_ShareBasedCompensation	44,058us-gaap_ShareBasedCompensation
Depreciation and amortization	49,292	48,071	39,940
Other	340us-gaap_OtherNoncashIncomeExpense	844us-gaap_OtherNoncashIncomeExpense	4,864us-gaap_OtherNoncashIncomeExpense
Changes in operating assets and liabilities:
Increase in accounts receivable	(206,887)	(64,575)	(89,856)
Increase in accounts payable and accrued expenses	153,424	44,150	30,625
(Decrease) increase in income taxes payable, net	(12,998)	8,435	1,441
Increase in other current assets	(3,270)	(2,015)	(63)
Net cash from operating activities	394,966	407,536	370,126
Investing Activities:
Purchase of short-term investments	(136,726)	(116,116)	(15,879)
Proceeds from maturities of short-term investments	122,726	89,915	16,221
Purchase of property and equipment	(37,472)	(53,411)	(47,626)
Escrow deposit for land acquisition	(27,101)	0	0
Other, net	(338)	2,806	290
Net cash from investing activities	(78,911)	(76,806)	(46,994)
Financing Activities:
Proceeds from issuance of common stock	69,269us-gaap_ProceedsFromStockPlans	59,752us-gaap_ProceedsFromStockPlans	52,511us-gaap_ProceedsFromStockPlans
Repurchases of common stock	(550,781)	(261,936)	(302,414)
Excess tax benefits from stock plans	1,115	2,339	5,401
Dividends paid	(124,634)us-gaap_PaymentsOfDividendsCommonStock	(123,292)us-gaap_PaymentsOfDividendsCommonStock	(117,263)us-gaap_PaymentsOfDividendsCommonStock
Purchase of noncontrolling interest	0us-gaap_PaymentsToMinorityShareholders	(7,730)us-gaap_PaymentsToMinorityShareholders	0us-gaap_PaymentsToMinorityShareholders
Distributions to noncontrolling interest	(503)	(1,161)	(1,282)
Net cash from financing activities	(605,534)	(332,028)	(363,047)
Effect of exchange rate changes on cash and cash equivalents	(31,066)	(11,892)	6,401
Decrease in cash and cash equivalents	(320,545)	(13,190)	(33,514)
Cash and cash equivalents at beginning of year	1,247,652	1,260,842	1,294,356
Cash and cash equivalents at end of year	927,107	1,247,652	1,260,842
Taxes Paid:
Income taxes	$ 254,439us-gaap_IncomeTaxesPaidNet	$ 235,368us-gaap_IncomeTaxesPaidNet	$ 207,174us-gaap_IncomeTaxesPaidNet

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.