CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 170,369	$ 185,895
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of trademark	24	24
Depreciation and other amortization	10,313	10,069
Gain on disposal of property and equipment	(216)	(50)
Stock-based compensation	14,392	13,631
Loss on put option	243	1,225
Gain on investments, net	(2,881)	(1,586)
Deferred income taxes	(926)	2,574
Tax benefit from exercise of stock options	(28,883)	(2,922)
Effect on cash of changes in operating assets and liabilities:
Accounts receivable	(104,993)	(87,833)
Distributor receivables	(5,310)	(17)
Inventories	(33,972)	(44,289)
Prepaid expenses and other current assets	(8,523)	640
Prepaid income taxes	(4,118)	(2,444)
Accounts payable	16,877	45,058
Accrued liabilities	15,987	25,260
Accrued promotional allowances	22,188	(24,609)
Accrued distributor terminations	3,464	(77)
Accrued compensation	(4,122)	(2,509)
Income taxes payable	33,019	(5,029)
Deferred revenue	6,788	(2,942)
Net cash provided by operating activities	99,720	110,069
CASH FLOWS FROM INVESTING ACTIVITIES:
Maturities of held-to-maturity investments	107,416	316,474
Sales of available-for-sale investments		33,391
Sales of trading investments		16,540
Purchases of held-to-maturity investments	(154,525)	(397,278)
Purchases of available-for-sale investments		(5,002)
Purchases of property and equipment	(22,497)	(19,880)
Proceeds from sale of property and equipment	8,665	226
Additions to intangibles	(5,101)	(2,503)
(Increase) decrease in other assets	(4,538)	485
Net cash used in investing activities	(70,580)	(57,547)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments on debt	(794)	(1,091)
Tax benefit from exercise of stock options	28,883	2,922
Issuance of common stock	16,288	6,437
Purchases of common stock held in treasury	(13,396)
Net cash provided by financing activities	30,981	8,268
Effect of exchange rate changes on cash and cash equivalents	1,204	(954)
NET INCREASE IN CASH AND CASH EQUIVALENTS	61,325	59,836
CASH AND CASH EQUIVALENTS, beginning of period	222,514	359,331
CASH AND CASH EQUIVALENTS, end of period	283,839	419,167
Cash paid during the period for:
Interest	19	28
Income taxes	$ 82,720	$ 115,311