Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities:
Net earnings	$ 459,497	$ 379,460	$ 350,011
Adjustments to reconcile net earnings to net cash from operating activities:
Provision for losses on accounts receivable	2,173	763	2,116
Deferred income tax expense (benefit)	17,999	(6,576)	(20,975)
Excess tax benefits from stock plans	(1,850)	(1,115)	(2,339)
Stock compensation expense	43,415	42,533	43,813
Depreciation and amortization	46,012	49,292	48,071
Other	(24)	340	844
Changes in operating assets and liabilities:
Decrease (increase) in accounts receivable	62,619	(206,887)	(64,575)
(Decrease) increase in accounts payable and accrued expenses	(84,164)	153,424	44,150
Increase (decrease) in income taxes payable, net	18,382	(12,998)	8,435
Decrease (increase) in other current assets	653	(3,270)	(2,015)
Net cash from operating activities	564,712	394,966	407,536
Investing Activities:
Purchase of short-term investments	(47,026)	(136,726)	(116,116)
Proceeds from maturities of short-term investments	87,320	122,726	89,915
Purchase of property and equipment	(44,383)	(37,472)	(53,411)
Escrow deposit for land acquisition	0	(27,101)	0
Other, net	(3,337)	(338)	2,806
Net cash from investing activities	(7,426)	(78,911)	(76,806)
Financing Activities:
Proceeds from issuance of common stock	130,964	69,269	59,752
Repurchases of common stock	(629,991)	(550,781)	(261,936)
Excess tax benefits from stock plans	1,850	1,115	2,339
Dividends paid	(135,673)	(124,634)	(123,292)
Purchase of noncontrolling interest	0	0	(7,730)
Distributions to noncontrolling interest	(2,122)	(503)	(1,161)
Net cash from financing activities	(634,972)	(605,534)	(332,028)
Effect of exchange rate changes on cash and cash equivalents	(41,625)	(31,066)	(11,892)
Decrease in cash and cash equivalents	(119,311)	(320,545)	(13,190)
Cash and cash equivalents at beginning of year	927,107	1,247,652	1,260,842
Cash and cash equivalents at end of year	807,796	927,107	1,247,652
Taxes Paid:
Income taxes	$ 239,367	$ 254,439	$ 235,368